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  • >> GOOD AFTERNOON, EVERYONE.

  • THIS IS A SPECIAL DAY BECAUSE WE

  • ARE IN THE FIRST DAY OF THE NIH

  • RESEARCH FESTIVAL AND A SPECIAL

  • DAY BECAUSE WE HAVE A REMARKABLE

  • LECTURER AS PART OF OUR REGULAR

  • WEDNESDAY AFTERNOON SERIES WHO

  • IS HERE TO TEACH US SOMETHING

  • PRETTY INTERESTING ABOUT VIRAL

  • HEMORRHAGIC FEVER, SPECIFICALLY EBOLA VIRUS.

  • ERICA OLLMANN SAPHIRE HAS AN

  • INTERESTING AND VERY PRODUCTIVE

  • CAREER BRINGING HER TO WHERE SHE

  • IS A PROFESSOR IN IMMUNOLOGY AND

  • MICROBIAL SCIENCE AT THE SCRIPPS

  • RESEARCH INSTITUTE.

  • WE FOUND A PROFILE OF HER IN THE

  • SAN DIEGO UNION TRIBUNE WHERE

  • SHE WAS CALLED, THE VIRUS

  • HUNTER.

  • AND VARIOUS COMMENTS WERE MADE

  • ABOUT HER CONTRIBUTIONS, WHICH

  • ARE OBVIOUSLY SUBSTANTIAL.

  • I WON'T COMMENT UPON WHAT THEY

  • CALLED HER, ALIAS, STEEL

  • MAGNOLIA.

  • I THOUGHT THAT WAS ODD TO BE

  • PUTTING IN A PROFILE OF A

  • SCIENTIST BUT YOU CAN DECIDE FOR

  • YOURSELF.

  • SHE GOT HER UNDERGRADUATE DEGREE

  • AT RICE WITH A DOUBLE MAJOR IN

  • BIOCHEM AND CELL BIOLOGY AND

  • ECOLOGIY AND EVOLUTIONARY

  • BIOLOGY AND PH.D. AT THE SCRIPPS

  • IN THE YEAR 2000.

  • AND HAS BEEN THERE IN THIS

  • REMARKABLE PRODUCTIVE ENTERPRISE

  • FOCUSED ON TRYING TO UNDERSTAND

  • HOW PATHOGENS EVADE AND USURP

  • THE INNATE AND ADAPTIVE IMMUNE

  • RESPONSES.

  • SHE HAS QUITE A DIVERSITY OF

  • PROJECTS GOING ON IN THE LAB

  • INCLUDING LASSA AND MARRER AND

  • EBOLA FEVER AND SHE IS AN EXPERT

  • IN INCORPORATING DIFFERENT

  • APPROACHES TO INTERESTING THIS

  • INCLUDING IMFROG NOLOGY AND

  • EXTRA CRYSTALLOGRAPHY --

  • IMMUNOLOGY -- AND I WANT TO

  • POINT OUT AT THE END OF THE

  • LECTURE, WE WILL HAVE TIME FOR

  • QUESTIONS AND THE MICROPHONES

  • ARE IN THE AISLE AND WELCOME TO

  • THOSE OF YOU WHO ARE WATCHING ON

  • THE WEB.

  • WE'LL TRY TO BE SURE THAT

  • QUESTIONS ARE POSED FROM THE

  • MICROPHONE SO YOU CAN HEAR THEM

  • AND THEN AT 4:00, WE'LL ADJOURN

  • DOWN THE HALL FOR CONTINUATION

  • OF INFORMAL CONVERSATIONS WITH

  • OUR SPEAKER BUT ALSO THE ACTUAL

  • FORMAL UNVEILING OF THE NEW FAES

  • CENTER, WHICH I THINK YOU'LL

  • WANT TO COME AND HAVE A LOOK AT

  • BECAUSE IT IS REALLY QUITE

  • BEAUTIFUL FACILITY AND WE'LL

  • HAVE A RIBBON CUTTING AND A FEW

  • HOPEFULLY SHORT SPEECHES AND

  • THAT WILL MORPH INTO A POSTER

  • SESSION WHERE THE SCIENTIFIC

  • DIRECTORS WHO ARE THEMSELVES

  • STANDING BY THEIR POSTERS

  • TALKING ABOUT THEIR SCIENCE

  • GIVING YOU A CHANCE TO HAD THE

  • THEM UP WITH REALLY HARD

  • QUESTIONS.

  • SO IT WILL BE QUITE AN

  • AFTERNOON.

  • BUT, TO GET US GOING HERE, IN MA

  • SUR, LET ME ASK YOU PLEASE TO,

  • GIVE A WARM WELCOME TO ERICA

  • OLLMANN SAPHIRE.

  • [ APPLAUSE ]

  • >> THANK YOU, DR. COLLINS.

  • IT'S A REAL PLEASURE TO BE HERE.

  • MY LABORATORY WORKS ON A LOT OF

  • DIFFERENT VIRUSES.

  • TODAY I'M GOING SHOW YOU CHAMPS

  • FROM TWO OF THEM.

  • THE FIRST ONE IS EBOLA VIRUS, A

  • LONG VIRUS AND THE SECOND ONE IS

  • A SMALLER ROUNDER PARTICLE AND

  • IT BELONGS TO THE ARENA VIRUS

  • FAMILY.

  • WHAT THEY HAVE IN COMMON IS A

  • SIMILAR DISEASE.

  • THEY BOTH CAUSE HEMORRHAGIC

  • FEVER AND THE SYMPTOMS LOOK

  • SIMILAR ESPECIALLY AT FIRST.

  • WHEREAS EBOLA IS QUITE RARE,

  • LASSA IS UNFORTUNATELY EXTREMELY

  • COMMON.

  • THERE ARE HUNDREDS OF THOUSANDS

  • OF CASES EVERY YEAR IN WESTERN

  • AFRICA AND THE FEVER IS MOST

  • FREQUENTLY IS IMPORTED TO THE

  • UNITED STATES AND EUROPE.

  • NOW WHAT ELSE THESE VIRUS VS. IN

  • COMMON IS A VERY SMALL GENOME.

  • EBOLA ENCODES SEVEN GENES LASSA

  • ONLY 4.

  • SO WHERE YOU HAVE 25,000 GENES

  • AND YOU CAN MAKE 25,000

  • PROTEINS, THESE VIRUSES MAKE

  • ONLY A FEW.

  • SO, USING THIS VERY LIMITED

  • PROTEIN TOOLKIT, HOW DOES A

  • VIRUS ACHIEVE ALL THE DIFFERENT

  • FUNCTIONS OF THE VIRUS LIFE

  • CYCLE FROM ATTACH WANT TO A NEW

  • HOST CELL, FUSION AND ENTRY AND

  • ENCODING AND TRANSCRIPTIONS AND

  • ASSEMBLY AND EXIT AND SOME OF

  • THE MORE SOPHISTICATED FUNCTIONS

  • FOR LOTS OF DIFFERENT PATHWAYS.

  • HOW DO THEY DO THAT?

  • ONLY A VERY FEW PROTEINS AT

  • THEIR DISPOSAL.

  • THIS IS THE GENOME OF LASSA

  • VIRUS.

  • THOSE ARE -- THAT WAS EBOLA AND

  • THIS IS LASSA.

  • SO HOW DOES A HANDFUL OF

  • PROTEINS CONSPIRE TO CREATE SUCH

  • EXTRAORDINARY PATHOGENESIS IN

  • HEMORRHAGIC FEVER?

  • THE ANSWER IS THAT EACH PROTEIN

  • THESE VIRUSES DO ENCODE IS

  • ESSENTIAL.

  • THESE VIRUS VS. NO JUNK.

  • MANY OF THESE PROTEINS ARE

  • MULTI-FUNCTIONAL AND SOME ARE

  • EXTREMELY ADAPTABLE.

  • BY STUDYING THE PROTEINS THESE

  • VIRUSES MAKE, WE SEE THE

  • VULNERABILITIES OF THE VIRUS,

  • THE ACHILLES HEEL, THE PLACE TO

  • TARGET A DRUG OR VACCINE OR

  • ANTIBODY.

  • BUT PERHAPS MORE IMPORTANTLY, WE

  • CAN UNDERSTAND SOMETHING MORE

  • ABOUT PROTEINS THEMSELVES.

  • BECAUSE EVOLUTION HAS COMPELLED

  • THESE PROTEINS TO BE REMARKABLE,

  • TO DO MORE WITH LESS THAN OTHER

  • PROTEINS BY STUDYING WHAT THESE

  • PROTEINS ARE CAPABLE OF, WE

  • LEARN ABOUT THE CAPABILITIES OF

  • PROTEINS IN MOLECULAR BIOLOGY.

  • SO I'LL SHOW YOU A FEW EXAMPLES.

  • THE FIRST ONE COMES FROM THE

  • FIRST STEP OF THE VIRUS LIFE

  • CYCLE.

  • SO THE FIRST STEP, THE VIRUS HAS

  • TO FIND AND ATTACH TO A NEW HOST

  • CELL.

  • THIS IS ACHIEVED BY THE

  • GLYCOPROTEIN CALLED GP.

  • BOTH VIRUSES EXPRESS ONLY ONE

  • PROTEIN ON THE SURFACE CALLED GP

  • AND IT IS SOLELY RESPONSIBLE FOR

  • ATTACHING WITH THAT CELL.

  • SO EBOLUS VIRUS FILAMENT US.

  • THIS HAS A MEMBRANE OF GREEN

  • SURROUNDING A NUCLEO CAP SID.

  • AND THERE ARE SPIKES.

  • THOSE ARE FORMING 450

  • KILLADALTON TRIMERS AND THEY ARE

  • QUITE HEAVILY GLYCOSYLATED.

  • SO THE QUESTION YOU MIGHT ASK

  • IS, IF THIS SPIKE IS IMPORTANT

  • FOR ATTACHMENT AND ENTRY, WHAT

  • DOES IT LOOK LIKE AND HOW DOES

  • IT WORK?

  • WE HAD TO MAKE ABOUT 140

  • VERSIONS OF THIS GP TO GET ONE

  • THAT WOULD CRYSTALLIZE WELAND WE

  • HAD TO THROW BACK 150.

  • BEFORE WE HAVE A STRUCTURE, WE

  • THINK OF A PROTEIN WITH AN END

  • TERMINUS AND C TERMINUS.

  • THIS IS CLEAVED IN THE PRODUCER

  • CELL, WITH 2 SUB UNITS.

  • A GP1 WHICH MEDIATES THE

  • RECEPTOR BINDING AND GP2 WHICH

  • MEDIATES FUSION.

  • SO THE BP1 HAS RECEPTOR BINDING

  • DOMAINS AND THE GP2 HAS TO

  • UNDERGO A CHANGE.

  • ALSO IN GP1 IS THIS UNUSUAL MUSE

  • IN-LIKE DOMAIN IT'S VERY HEAVILY

  • GLYCOSYLATED.

  • THERE IS A LOT OF UNSTRUCTURED

  • PROTEIN HERE.

  • SO THIS IS THE CRYSTAL STRUCTURE

  • OF THE EBOLA VIRUS GP.

  • YOU CAN SEE THE 3GP1 SUBUNITS IN

  • BLUE AND GREEN.

  • THESE RECEPTOR BINDING ARE TIED

  • TOGETHER AT THE BOTTOM BY THE

  • GP2 FUSION SUBUNITS.

  • NOW THERE IS SOMETHING

  • INTERESTING HERE.

  • WHEN YOU THINK ABOUT A FUSION

  • PEPTIDE OR FLU OR HIV, IT'S A

  • HYDROPHOBIC PEPTIDE TUCKED UP

  • INSIDE THE STRUCTURE.

  • HERE ARE THE FUSION LOOP IT IS

  • TACKED ON TO THE OUTSIDE.

  • THIS REACHES ALONG THE OUTSIDE

  • AND BINDS INTO THE NEXT ONE.

  • IN ORDER TO GET THIS TO

  • CRYSTALLIZE, WE HAD TO EXIZE AND

  • WE WANT TO UNDERSTAND WHAT THE

  • REAL GP LOOKS LIKE ON THE

  • SURFACE.

  • IT HAS HEAVILY GLYCOSYLATED

  • DOMAINS ATTACHED AT THE TOP.

  • NOTE GP ONE TAINING THAT DOMAIN

  • CRYSTALLIZES AND WE HAD TO USE A

  • DIFFERENT TECHNIQUE.

  • A SMALL SCATTERING, TINY X-RAYS

  • AND PROTEIN MOLECULES TUMBLING

  • AROUND IN SOLUTION GET A LOW

  • RESOLUTION VIEW, MAYBE 10

  • RESOLUTION.

  • AND THEN THIS, TURNS OUT THIS IS

  • THE SOLUTION SCATTERING ENVELOPE

  • OF THE GLYCOSYLATED EBOLA VIRUS

  • GP.

  • SO THE CRYSTAL SHUCK STRUCTURE

  • IS IN THE RIBBON CENTER.

  • SO THESE ARE THE DOMAINS

  • ATTACHED.

  • SO THE EFFECTIVELY TRIPLE THE

  • SIZE OF THE MOLECULE.

  • AND THIS IS A HELL OF A GLYCAN

  • SHE WOULD.

  • THEY REACH ABOUT 100 FROM THE

  • CORE OF THE G.

  • AND THEY ARE QUITE FLEXIBLE SO I

  • EXPECT THE ACTUAL WILT OF THIS

  • DOMAIN TO BE HALF THAT.

  • I THINK VISUALIZING THE

  • FLEXIBILITY AS WELL.

  • THE SALIENT FEATURE OF THIS IS

  • THAT THESE MUSE IN-LIKE DOMAINS

  • ARE MASSIVE AND THEY DOMINATE

  • THE STRUCTURE.

  • S OKAY?

  • SO THIS IS WHAT IS ON THE

  • BIOSURFACE.

  • HOW DOES IT WORK?

  • HOW DOES IT FIND AND GET INTO A

  • NEW CELL?

  • WELL, THIS I'M SHOWING AGAIN THE

  • CRYSTAL STRUCTURE AND COLORING

  • THE SURFACE WHITE.

  • PATCHES THAT ARE COLORED PINK

  • ARE AREAS THAT MUTAGENESIS TELLS

  • US ARE IMPORTANT FOR

  • INFECTIVITY.

  • THEY ARE SEQUESTERED INSIDE THE

  • BOWL SHIP THAT IT MAKES.

  • THE RESIDUES MOST IMPORTANT TO A

  • SEPARATE BINDING ARE VERY

  • SEQUESTERED.

  • INSIDE STRUCTURE UNDER THIS

  • DOMAIN.

  • SO THAT IS SORT OF A

  • REPRESENTATION OF WHERE THE

  • DOMAINS ARE.

  • THE PARTS THAT ARE IMPORTANT FOR

  • THE RECEPTOR BINDING ARE PINK

  • AND THEY ARE UNDER THESE DOMAINS

  • CALLED THE GLYCAN CAP.

  • SO, DOES THIS MAKE INNOCENCE HOW

  • ON EARTH IS THIS AFFECTED UNDER

  • THIS ENTIRE CANOPY OF PROTEIN

  • CARBOHYDRATES?

  • THE ANSWER IS THAT IT IS KNOWN

  • FROM BIOLOGY THAT GP NEEDS TO BE

  • CLEAVED BY HOST CAPSAICIN

  • ENZYMES FOR THIS TO OCCUR.

  • THIS IS ESPECIALLY IMPORTANT FOR

  • EBOLA VIRUS.

  • SO, WHY?

  • WELL, IN SOLVING THE CRYSTAL

  • STRUCTURE, WE SEE THAT ALL OF

  • THIS STRUCTURE, THE GLYCAN CAP

  • AND THE WHOLE MUSE IN LIKE

  • DOMAIN ARE ATTACHED BY A SINGLE

  • POLYPEPTIDE TETH THEY'RE

  • CONNECTS RESIDUE 189 TO 213.

  • AND THAT PIECE OF POLYPEPTIDE IS

  • DISORDERS.

  • SO SOMETHING THAT IS DISORDER IN

  • A CRYSTAL STRUCTURE AND FLEXIBLE

  • AND MOVING AROUND.

  • SO THIS LOOKS LIKE A PRETTY

  • ATTRACTIVE CLEAVAGE SITE.

  • IF PROTEASES WERE TO CLEAVE ON

  • THAT YELLOW LOOP, THIS WOULD BE

  • THE EFFECT.

  • A MUCH BETTER EXPOSURE.

  • NOW WE ARE NOT MAKING THAT UP.

  • THIS IS ACTUALLY THE CRYSTAL

  • STRUCTURE NOW CLEAVED GP AND

  • ANOTHER LAP SHOWS THAT YES,

  • CLEAVAGE STRIPS OFF 85% OF THE

  • MASS OF GP1 LEAVING THE RECEPTOR

  • BINDING SITES EXPOSED.

  • SO IN IS WHAT THE PROTEIN

  • LOOKS LIKE ON THE VIRAL SURFACE.

  • WHAT DO WE LEARN FROM THIS?

  • RECEPTOR BINDING PROBABLY

  • DOESN'T HAPPEN AT THE VIRAL

  • SURFACE.

  • BY LOOKING AT THE STRUCTURE, YOU

  • CAN SEE SPOTS NEEDED TO BIND

  • THAT RECEPTOR ARE NOT

  • ACCESSIBLE.

  • THEY ARE NOT WELL EXPOSED IN

  • THIS KIND OF PROTEIN.

  • INSTEAD, THE VIRUS THAT BEARS

  • THIS SURFACE ENTERS CELLS BY

  • MACRO 15AL CYTOSIS.

  • ONCE IN THE ENDOSOME, THIS IS

  • CLEAVED TO STRIP OFF ALL THAT

  • SURFACE SUGAR IN THE MEW SIN

  • LIKE DOMAINS LEAVING THE

  • RECEPTOR BINDING SITE EXPOSED

  • AND ALLOWING BINDING BY THE

  • RECEPTOR AND THIS BINDING SITE

  • IS RIGHT THERE WHERE THE GLYCAN

  • CAP USED TO BE.

  • SO WHAT WE SEE HERE IS ONE

  • POLYPEPTIDE AND ALSO TWO

  • DIFFERENT BIOLOGICALLY RELEVANT

  • MANIFESTATIONS.

  • THIS IS THE MOLECULE SUBJECT TO

  • ANTIBODY SURVEILLANCE AND THIS

  • IS THE MOLECULE FUNCTIONAL FOR

  • RECEPTOR BINDING.

  • SO WHAT DOES THAT MEAN TO THE

  • IMMUNE RESPONSE?

  • WELL, NOTHING GOOD.

  • MANY CAN BE CLIPPED OFF.

  • A LOT OF VACCINATION STUDIES,

  • THESE SITES CAN BE

  • IMMUNODOMINANT.

  • YOU CAN SEE THAT ANY ANTIBODY

  • THAT BINDS TO THESE EPITOPES

  • WILL BE CUTTING RIGHT OFF IN THE

  • END ZOME LEAVING A RECEPTOR

  • BINDING CORE THAT IS NOW

  • ANTIBODY FREE.

  • THOSE KINDS OF ANTIBODIES DON'T

  • NEUTRALIZE.

  • THE ESSENTIAL CONSERVED SITES

  • ARE NOT WELL EXPOSED.

  • SO FOR EXAMPLE, ALL OF THESE

  • VIRUSES SHARE THE SAME RECEPTOR

  • SO THAT'S A CONSERVED BINDING

  • SITE, AN ESSENTIAL SITE FOR THE

  • MOLECULE.

  • WE WOULD LIVE TO TARGET THAT

  • WITH ABET BODY.

  • IT'S PARTIALLY HIDDEN UNDER THE

  • CAP AND VIRAL SURFACE SO THE

  • ANTIBODY MIGHT NOT SEE IT UNLESS

  • YOU FOUND A WAY TO ENGINEER THE

  • ANTIBODY.

  • BECAUSE OF THIS CAN NUN DRUM, WE

  • ARE LEFT A PUZZLE THAT

  • NEUTRALIZATION AND PROTECTION

  • DON'T ALWAYS CORRELATE EBOLA

  • VIRUS.

  • SO NEUTRALIZATION IS YOUR

  • ABILITY TO INACTIVATE THE VIRUS

  • IN VITRO.

  • PRO SECTION YOUR ABILITY TO SAVE

  • THE ANIMAL IN VIVO.

  • SO FOR EXAMPLE, ANTIBODIES LIKE

  • THIS, THIS IS THE HUMAN KZ52

  • FROM THE SURVIVOR.

  • OUTBREAK NEUTRALIZES BRILLIANTLY

  • AND DOESN'T PROTECT.

  • ANTIBODIES LIKE THESE, INCLUDING

  • TWO THAT BIND THE MUSE IN LIKE

  • DOMAINS, DON'T NEUTRALIZE BUT

  • THEY DO PROTECT THE PRIMATE.

  • SO THIS DOESN'T MAKE A LOT OF

  • SENSE.

  • LEAVING YOU WONDERING WHAT WORKS

  • HERE.

  • WE HAD THIS RESULT YEARS BEFORE

  • AND IT REALLY COOLED EVERYBODY'S

  • OPINION ON ANTIBODIES AGAINST

  • EBOLA VIRUS THINKING WHETHER IT

  • WOULD BE POSSIBLE TO PROTECT

  • ANIMALS T TURNS OUT THAT YOU

  • CAN.

  • THESE ARE QUITE PROTECTED.

  • EVEN IF YOU WAIT LONG ENOUGH FOR

  • HEMORRHAGIC FEVER TO DEVELOP.

  • THE DIFFERENCE MIGHT BE THAT

  • THESE ARE GIVEN IN A COCKTAIL AS

  • THIS WAS GIVEN ALONE.

  • SO DOES THAT MEAN WE HAVE TO

  • HAVE A COCKTAIL?

  • IS THE LENGTH AND THE NUMBER OF

  • EBOWL VIRUS SUCH THAT WE NEED TO

  • HAVE MULTIPLE ANTIBODIES AGAINST

  • MULTIPLE ESTIMATES IF SO, WHICH

  • ONES DO WE PUT TOGETHER?

  • TWO-THIRDS OF THIS COCKTAIL SELL

  • MUSE IN.

  • DOES THAT MEAN THAT IT WORKS?

  • OR IS THIS ONE THE CHAMP THAT

  • BINDS THE TOP?

  • WE DON'T KNOW.

  • NOW IN THE FIELD WE HAVE ABOUT

  • 200 DIFFERENT MONOCLONAL

  • ANTIBODIES IDENTIFIED IN THIS

  • VIRUS.

  • WHAT DO YOU PUT TOGETHER IN A

  • COCKTAIL.

  • NOW I'M GOING DIVERT A LITTLE

  • BIT FROM MY THEME WHEN THE

  • PROTEINS OF THE VIRUS AND THEN

  • TELL YOU HOW TO USE THE

  • STRUCTURE TO GET AT THAT

  • PROBLEM.

  • THIS IS THE WEBSITE THAT THE

  • VIRAL HEMORRHAGIC FEVER -UE CAN

  • FIND THIS LINK THROUGH SCRIPPS

  • VERY SOON.

  • THIS IS MORE THAN 20PIs AND 7

  • DIFFERENT COUNTRIES HAVE GOTTEN

  • ON THE SAME PAGE.

  • WE PUT ALMOST ALL THE ANTIBODIES

  • KNOWN AGAINST THESE VIRUSES

  • TOGETHER IN ONE POOL.

  • WE BLINDED THEM AND THEN COMPARE

  • THEM SIDE-BY-SIDE TO SEE WHAT IS

  • MORE EFFECTIVE.

  • IN OTHER WORDS HOW TO PUT

  • TOGETHER THE RIGHT COCKTAIL.

  • RIGHT NOW WE HAVE THREE FROM THE

  • ARMY IN A COOK TAIL THAT

  • NEUTRALIZE AND WE HAVE THREE

  • FROM CANADA IN A COCKTAIL THAT

  • NEUTRALIZES.

  • WHAT IF THE MOST EFFECTIVE IS

  • ONE FROM JAPAN AND ONE FROM THE

  • ARMY AND ONE FROM HAMILTON?

  • WE WON'T KNOW UNTIL WE PUT THEM

  • ALL TOGETHER IT'S NICE THAT

  • EVERYONE IS ON THE SAME PAGE IN

  • THE SAME STUDY.

  • SO UNTILE WOO MAKE THAT

  • COCKTAIL, LET'S ASSUME THAT

  • VIRAL INFECTION WILL PIQUE.

  • SO THE NEXT VIRAL INFECTION

  • AFTER THE VIRAL MEMBRANE IS

  • FUSED TO THE HOST ENDOSOME

  • MEMBRANE AND GENETIC MATERIAL

  • EXCERPTS THE VIRUS STARTS TO

  • REPLICATE.

  • NOW, SOMETHING IMPORTANT HAPPENS

  • HERE.

  • MOST PEOPLE DIE FROM EBOLA VIRUS

  • INFECTION.

  • 50-90%.

  • SOME PEOPLE LIVE.

  • WHAT SILENT DIFFERENCE?

  • THE DIFFERENCE SEEMS TO BE THAT

  • THOSE PEOPLE THAT SURVIVE THE

  • EBOLA VIRUS INFECTION TEND TO

  • GENERATE AN EARLY AND STRONG

  • IMMUNE RESPONSE AGAINST THE

  • VIRUS AND THE VIRAL TITER STARTS

  • TO DROP BY AROUND DAY 4.

  • THOSE PEOPLE THAT ULTIMATELY

  • SUCCUMB TO THE VIRUS INFECTION

  • ARE MORE LIKELY TO BE

  • CHARACTERIZED BY A VERY POOR

  • IMMUNE RESPONSE AND THEIR VIRAL

  • TITERS GET QUITE HIGH.

  • 10 TO THE 9 TO 10 TO THE 10.

  • SO FOR THIS DECISION POINT

  • TO OCCUR BY AROUND DAY 4, THAT

  • MEANS THAT THE INNATE IMMUNE

  • SYSTEM IS QUITE IMPORTANT IN

  • MAKING THIS DECISION OF SURVIVAL

  • OR NOT SURVIVAL.

  • SO WHAT IS THE VIRAL FACTOR AT

  • PLAY IN THIS AMAZING DECISION

  • POINT?

  • ONE OF THEM IS A PROTEIN CALLED

  • VP35.

  • VIRAL PROTEIN 35 KILL DALTONS.

  • IT'S A COMPONENT OF THE NUCLEO

  • CAPS IN REPLICATION COMPLEX.

  • IT ALSO HAS ANOTHER JOB,

  • INTERFERON ANTAGONIST.

  • WHAT IT DOES IS BIND

  • DOUBLE-STRANDED RNA.

  • NOW YOU TYPICALLY WOULD ONLY

  • HAVE DOUBLE-STRANDED RNA IN THE

  • CONTEXT OF A VIRAL INFECTION.

  • SO IT IS A PATHOGENESIS

  • MOLECULAR POWDER.

  • YOUR INNATE IMMUNE SYSTEM THAT

  • HAS SENSORS LOOKING FOR

  • DOUBLE-STRANDED RNA AND THEY

  • MOUNT A ANTIVIRAL RESPONSE.

  • SO HOW DOES THIS WORK?

  • THIS IS A CRYSTAL STRUCTURE VP35

  • BOUND TO DOUBLE-STRANDED RNA.

  • SO THE DOUBLE-STRANDED RNA

  • APPEARS IN GREEN.

  • WE HAVE FOUR COPIES OF VP35

  • BOUND TO IT.

  • NOW THIS HALF IS IDENTICAL TO

  • THIS HALF IN THE STRUCTURE.

  • SO YOU CAN REALLY ONLY LOOK THAT

  • THE HALF IF YOU WANT.

  • THIS IS NOT THE MODE OF GLYCAN

  • BINDING YOU LEARNED ON YOUR

  • MOTHER'S KNEE AS A BIOCHEMIST.

  • WHAT YOU TIICALLY THINK OF WHEN

  • YOU THINK OF A PROTEIN BINDING A

  • LIGAND, IT HAS ONE BINDING SITE.

  • THIS LASER POINTER IS A LIGAND.

  • MY HAND IS THE PROTEIN, IT BINDS

  • IN THE PALM AND THAT IS THE

  • BINDING SITE.

  • PERFECTLY SHAPED.

  • WHAT WE HAVE HERE IS THE SAME

  • PROTEIN BINDING IN TWO DIFFERENT

  • WAYS.

  • TWO COPIES BIND THE BACKBONE,

  • TWO COPIES CAP THE END OF THE

  • THESE ARE THE IDENTICAL

  • PROTEINS.

  • YOU CAN PULL OFF THE END CAP AND

  • ROLE IT AROUND AND ATTACH IT BY

  • THE BACKBONE.

  • THEY USE DIFFERENT BINDING SITES

  • TO DO THIS.

  • THE END CAPPING HUGHES SYSTEM A

  • HYDROPHOBIC PATCH AND THE

  • BACKBONE USES A HYDROPHILIC

  • PATCH.

  • SO INSTEAD OF IT BINDING IN ONE

  • SITE, YOU HAVE TWO IDENTICAL

  • COPIES OF THE PROTEIN AND ONE

  • BINDS THIS WAY AND ONE BINDS

  • THIS WAY.

  • IT TURNS THOUGHT DIMERIZATION IS

  • ESSENTIAL.

  • POINT MUTATION THAT IS BROCK

  • THAT INTERFACE ATTENUATE THE

  • EBOLA VIRUS.

  • AFTER YOU FORM THIS DIMER ON THE

  • END, IT SPIRALS AROUND THE RNA.

  • IT IS INTERESTING THAT IT HAS

  • REPURPOSED ITSELF FROM NUCLEO

  • CAPSID PROTEIN TO HAVE THIS

  • ADDITIONAL FUNCTION AND USED

  • DIFFERENT SIDES OF ITSELF IN

  • ORDER TO MAKE TWO DIFFERENT

  • BANDING STATES.

  • BINDING SITES.

  • HERE IS THIS PROTEIN.

  • I'M GOING TO SHOW YOU THIS NEXT

  • WITH A DIFFERENT STRATEGY FOR

  • MANAGING DOUBLE-STRANDED RNA.

  • THIS IS THE NUCLEAR PROTEIN OF

  • LASSA VIRUS.

  • SO THE DAY JOB OF THE NUKE LA

  • PROTEIN IS TO BIND AND PLAY A

  • ROLE IN REPLICATING THE VIRAL

  • GENOME.

  • RNA VIRUS THAT IS PROTECT OUR

  • GENOME BY HAVING IT CONTINUALLY

  • BOUND BY A NUCLEO PROTEIN.

  • LASSA HAS FOUR GENES.

  • THIS PROTEIN HAS ANOTHER

  • FUNCTION THAT IS ALSO INTERFERON

  • ANTAGONIST.

  • BUT IT WAS KNOWN THAT IT WAS

  • IMMUNOSUPPRESSIVE BUT IT WASN'T

  • KNOWN HOW.

  • SO HOW DOES THIS GENOME BINDING

  • PROTEIN SUPPRESS IMMUNE

  • SIGNALING?

  • WE DIDN'T KNOW.

  • SO WE SOLVED THE STRUCTURE.

  • HERE IS THE STRUCTURE.

  • IT HAS STRANDS, HELIXES AND

  • LOOPY BITS AND BOUND ZINC.

  • THAT DEPENDENT TELL US ANYTHING.

  • -- THAT DIDN'T TELL US ANYTHING.

  • THIS LOOKS LIKE ANOTHER NUCLEO

  • VIRUS.

  • SO WE HAVEN'T LEARNED ANYTHING

  • FROM THE SEQUENCE.

  • SO WE ASKED OURSELVES IS IT

  • STRUCTURE LIKE ANYTHING WE SEEN

  • BEFORE?

  • EACH THOUGH THE SEQUENCE ISN'T.

  • SO WE DID A DOLLY SEARCH FOR

  • THINGS OF SIMILAR FOLD AND WE

  • FOUND ONE.

  • SO IN GREEN, SILENT LASSA VIRUS

  • NUCLEO PROTEIN.

  • I'M GOING DO OVERLAY OTHER

  • PROTEINS WHICH ARE ALL NUCLEASES

  • OF THE DEDDH SUPER FAMILY.

  • THIS IS ISG20.

  • DNA POLYMERASE SUBUNITS.

  • THE FOLDS ARE SIMILAR.

  • THEY HAVE THE SECONDARY

  • STRUCTURAL ELEMENTS IN THE SAME

  • PLACES.

  • THIS THE SILENT SUPER FAMILY OF

  • NUCLEASES -- IT HAS A SIMILAR

  • FOLD EVEN RIGHT DOWN TO THE

  • NUCLEOAISE ACTIVE SITE.

  • SO ALL OF THESE ENZYMES ARE

  • CHARACTERIZED BY THE DEDDH.

  • THESE CATALYTIC RESIDUES.

  • THE LASSA NUCLEAR PROTEIN IS

  • COLORED GREEN.

  • IT HAS THE SAME RESIDUES IN THE

  • SAME PLACE.

  • IF YOU LOOKED IN THE SEQUENCE,

  • YOU COULD SEE THEY WERE THERE

  • AND THEY ARE ACROSS THE IMMUNEOY

  • VIRUSES BUT THE SPACING WASN'T

  • ANYTHING YOU COULD APPRECIATE

  • THAT WOULD WIND UP BEING AN

  • EXNUCLEASE UNTIL WE SAW THE

  • STRUCTURE.

  • SO IT LOOKS LIKE A EXNUCLEASE

  • DOES. IT FUNCTION LIKE ONE?

  • SO TO ANSWER THAT, WE GIVE IT

  • DNA, RNA, SINGLE STRANDED AND

  • DOUBLE-STRANDED AND IT DIGESTED

  • SOME OF THEM.

  • SO THIS DIGESTS NUCLEIC ACID AND

  • DOUBLE-STRANDED RNA.

  • SO THE OTHER EXNUCLEASES IN THE

  • SUPER FAMILY CAN BE MORE

  • CATHOLIC IN THEIR SPECIFICITY.

  • THIS ONE ONLY DIEGISTS

  • DOUBLE-STRANDED RNA.

  • THE PATHOGENESIS MOLECULAR

  • PALTERERN.

  • WE THINK THAT ENZYMATIC ACTIVITY

  • IS LINKED TO THE

  • IMMUNOSUPPRESSION.

  • BECAUSE WHEN YOU MAKE POINT MUTE

  • APPOINTMENTS AROUND THE ACTIVE

  • SITE, THE WILDTYPE PROTEIN

  • DIEGISTS DOUBLE-STRANDEDS RNA.

  • THE MUTANTS DON'T.

  • IF YOU LOOK AT A REPORTER

  • ACTIVITY, THE WILDTYPE POE TEEN

  • SUPRESS IT IS AND THE MUTANTS

  • DON'T.

  • SO IF YOU KNOCKOUT THE

  • EXNUCLEASE ACTIVITY, YOU

  • KNOCKOUT THE IMMUNOSUPPRESSION.

  • HERE IS A STRUCTURE OF THE

  • NUCLEASE COMPLEX DOUBLE-STRANDED

  • RNA.

  • THE YELLY FEEDS INTO THE ACTIVE

  • SITE.

  • THE PAIRED PURPLE STRAND ARCHES

  • UP.

  • AND WE CAN LOOK IN HERE AND

  • COMPARE THIS TO OTHER

  • EXNUCLEASES AND SEE THERE ARE

  • ONLY TWO AMINO ASATOIDS GIVE THE

  • UNIQUE IMMUNOSUPPRESSIVE

  • SPECIFICITY.

  • SO WHAT IT IS DOING IS MAYBE

  • RAPIDLY ERASING THE THING THE

  • IMMUNE SYSTEM IS LOOKING FOR.

  • DOUBLE-STRANDED RNA IS A

  • REPLICATION INTERMEDIATE OF A

  • SINGLE STRANDED RNA VIRUS MAYBE

  • AS ONE DOMAIN BINDS, THE OTHER

  • COMES ALONG AND RAISES IT.

  • WE ARE STILL TRYING TO FIGURE

  • OUT HOW THAT WORKS.

  • WE SEE THAT THIS STRUCTURE AND

  • THAT MOTIF SEEMS TO BE SHARED

  • AMONG THE ARENA VIRUS FAMILY.

  • THIS IS A FAMILY OF 50 DIFFERENT

  • VIRUSES THAT ARE EXISTING NEARLY

  • EVERY CONTINENT.

  • SO, AN ENZYME WITH A NUMBER OF

  • HUMAN PATHOGENS LOOKS LIKE IT

  • COULD BE AN EFFECTIVE TARGET FOR

  • BROAD SPECTRUM ANTIVIRAL AND I'M

  • LOOKING FOR SOMEONE TO WORK WITH

  • ME ON THAT.

  • SO WHAT WE SEE HERE AND THIS

  • EXAMPLE IS A POLYTEP TIED WITH

  • MULTIPLE ACTIVITIES.

  • IT'S DAY JOB IS TO ERASE A KEY

  • SIGNATURE TO SPARK INNATE IMMUNE

  • SIGNALING.

  • SO THE VIRUS HAS ENTER THE THE

  • CELLS, SUPPRESSED IMMUNE

  • SIGNALING AND REPLICATED AND ITS

  • NEXT JOB IS TO ASSEMBLE NEW

  • VARIANTS AND BUD OUT.

  • THAT OCCURS BY PROTEIN CALLED

  • MATRIX FOR EBOLA VIRUS IT'S

  • CALLED VP40.

  • SO THE MATRIX IS THE LAYER RIGHT

  • UNDER THE MEMBRANE BETWEEN THE

  • MEMBRANE AND THE NUCLEO CAPS IN

  • AND IT GIVES THE VIRUS ITS

  • SHAPE.

  • SO IF YOU TRANSFECT CELLS OF

  • VP40 ALONE IT WILL ASSEMBLE BUT

  • OUT VIRUS LIKE PARTICLES THAT

  • LOOK LIKE EBOLA VIRALS.

  • SO ALL THE INFORMATION YOU NEED

  • TO BUILD AND BUD A ENVELOPE

  • PARTICLE IS CONTAINED IN VP40.

  • SO, HOW DOES IT DO THAT?

  • WHAT DOES THIS PROTEIN LOOK

  • LIKE?

  • THE FIRST CRYSTAL STRUCTURE WAS

  • SOLVED 13 YEARS AGO NOW.

  • HERE IT IS.

  • AS AN N-TERMINAL DEMAIN AND A C

  • TERMINAL DOMAIN.

  • IT STILLS HAS TO BE A MONOMER.

  • WHAT IS INTERESTING ABOUT A

  • MATRIX PROTEIN IS NOT WHAT IT

  • LOOKS LIKE AS A MONOMER BUT HOW

  • IT ASSEMBLES, HOW TO BUILD A

  • MATRIX?

  • SO THEY KNEW THAT IF THEY

  • TINKERED WITH THE VP40, CUTTING

  • OFF C TERMINAL TO RENALONS OR

  • OTHERS, THEY COULD GET TO THE TO

  • FORM RINGS.

  • SO HERE IS EM OF A HEX MERIC

  • RING AND A CRYSTAL STRUCTURE OF

  • THIS RING.

  • SO THEY EXPRESSED THE N-TERMINAL

  • DOMAIN WITH USE WITHOUT THE

  • ORANGE C TERMINAL DOMAIN.

  • EIGHT OF THEM MAKE THIS RING AND

  • UNEXPECTEDLY, IT PULLED OUT RNA

  • FROM THE E.COLI SYSTEM.

  • THERE IS A LITTLE ORANGE BOUND

  • TO EACH ONE OF THE EIGHT COPIES

  • OF VP40 IN THIS RING.

  • SO FOR THE LAST DECADE, THAT HAS

  • BEEN OUR ONLY MODEL FOR HOW VP40

  • COULD ASSEMBLE.

  • THIS IS A LOT OF EFFORT THAT HAS

  • GONE INTO DESIGNING DRUGS TO

  • INHIBIT RING FORMALIZE INHIBIT

  • MATRIX FORMATION.

  • A LOT OF MODELS GENERATED BY

  • TAKING THIS CHEERIO AND MAKING

  • LINOLEUM PATTERN AND WRAPPING IT

  • AROUND THE FILLA VIRUS.

  • BUT THERE ARE A NUMBER OF

  • PROBLEMS WITH THIS SLIDE.

  • THE FIRST ONE IS THE RINGS ARE

  • NOT FOUND IN PURIFIED VARIETIES.

  • SO IF THEY ARE NOT IN THE

  • VARIANT, ARE THEY A COM PONE

  • INNOCENT THEY ARE FOUND IN

  • INFECTED CELLS.

  • JUST NOT THE ACTUAL VIRUS.

  • THE SECOND PROBLEM IS THAT THERE

  • IS NO RNA IN THE VIRUS MATRIX

  • LAYER.

  • WHAT THAT WAS WASN'T ENTIRELY

  • CLEAR.

  • THE RN SAMPLE BOUND TO THE NUKE

  • LID CAPSID AT THE CENTER.

  • THE THIRD PROBLEM IS MUTATION

  • THAT IS PREVENT RING FORMATION

  • GAVE PERFECTLY NORMAL LOOKING

  • VIRAL PARTICLES.

  • SO IF YOU ABOLISH THE RING YOU

  • CAN BUD OUT A NORMAL LOOKING

  • VIRUS.

  • THE CRYSTALLING ONFERS DIDN'T

  • THINK THIS IS HOW THE MATRIX WAS

  • ASSEMBLED BECAUSE THEY DID ALL

  • THIS WORK BUT THE FIELD

  • PROCEEDED AS IF VP40 MADE THESE

  • RINGS, SOMETHING WAS HELD AS

  • SIMPLE.

  • HOW DOES IT ASSEMBLE?

  • WE DIDN'T INTEND DO DO ANY OF

  • THE WORK.

  • I'M GOING TO SHOW YOU THIS NEXT.

  • WE WERE MAKING VP40 FOR SOME

  • OTHER REASON.

  • AND WHAT WE NOTICE IS WHEN WE

  • PURIFY VP40, IT CAME OUT AS A

  • DIMER, NOT A MONOMER.

  • SO WE ARE USING SIZE EXCLUSION

  • ANGLE LIGHT SCATTERING.

  • SO IT'S A MORE SENSITIVE METHOD

  • IN TOMORROWING SOMETHING THAT

  • WASN'T WIDE LIVEABLE A DECADE

  • AGO.

  • SO VP40 WAS ALWAYS A DIMER.

  • DOES THAT MATTER?

  • WE WERE LOOKING FOR A DIFFERENT

  • WAY.

  • WE HAD ALL THIS PROTEIN, WE HAD

  • ROBOTS SO WOE GREW CRYSTALS AND

  • WE SOLVED 9 STRUCTURE.

  • HERE IS THE STRUCTURE.

  • WE SEE THE END TERMINAL AND C

  • TERMINAL.

  • SO THE STRUCTURE FROM DIMER IS

  • COLORED.

  • HERE IS THE STRUCTURE FROM THE

  • MONOMER.

  • NO CHANGE.

  • SO, THE REVELATION THAT IT WAS A

  • DIMER INSTEAD OF A MONOMER

  • HASN'T TOLD US ANYTHING ABOUT

  • THE FOLD OF THE PROTEIN.

  • BUT IT WAS THE PIECE OF

  • INFORMATION THAT WE NEEDED TO GO

  • LOOKING IN THE CRYSTAL PACKING.

  • BECAUSE WE KNEW THAT IT WAS A

  • DIMER IN SOLUTION.

  • SO SOMEHOW THOSE PROTEINS

  • ASSEMBLED IN THE CRYSTALS WE ARE

  • GOING TO SEE THE DIMER

  • INTERVASE.

  • THIS SILENT CRYSTAL PACKING.

  • -- THIS IS THE CRYSTAL PACKING.

  • C ARE BLUE, PROTEINS ARE

  • ORIENTED LIKE THIS DOWN A

  • FILAMENT SO THEY MAKE THIS

  • NNCCNNCC FILAMENT.

  • SOMEWHERE IN THIS IS THE DIMER

  • THAT FLOATS AROUND THE SOLUTION.

  • SO THE DIMER MADE BY THE

  • BLUE-BLUE OR THE ORANGE ORANGE

  • INTERACTION?

  • WELL, THE BLUE BLUE VARIES MORE

  • MOLECULAR SURFACE BUT THE PROOF

  • CAME FROM A POINT MUTATION WE

  • MADE, LEU117.

  • SO THE DIMER INTERNATION IS

  • PROBABLY THE BLUE ONE EXTHIS IS

  • THE DIME THEY'RE FLOATS AROUND

  • THE SOLUTION THAT LOOKS LIKE A

  • BUTTERFLY.

  • INCIDENTALLY THAT LEUCIN 117 IS

  • ON THE OUTSIDE OF THE RING.

  • IT'S NOT INVOLVED IN ANY RING

  • ASSEMBLING INTERFACESES.

  • SO LET'S HAVE ANOTHER LOOK AT

  • THAT FILL MEANT.

  • HERE THIS BELONGS TO EBOLA

  • VIRUS.

  • THIS IS THE SIDE VIEW.

  • ROLE IT AROUND AND THERE IS THE

  • TOP VIEW.

  • THIS IS HOW THE CRYSTALS

  • ASSEMBLE.

  • ALL THOSE FILAMENTS LINE UP

  • SIDE-BY-SIDE.

  • WELL, WE WONDERED IF THAT WAS

  • INTERESTING.

  • IS THIS ASSEMBLY PHYSICAL

  • LOGICALLY RELEVANT OR A

  • ARTIFACT?

  • THE ODD THING WE NOTICED IS THAT

  • NO MATTER HOW WE TRIED TO

  • CRYSTALLIZE VP40, WE ALWAYS GOT

  • THE SAME FILAMENT.

  • THIS GROUP C2, BASE GROUP

  • EXPLORE -- THIS IS THE ORIGINAL

  • STRUCTURE.

  • NO MATTER WHAT SPECIES WE WORKED

  • WITH OR WHICH CRYSTAL SYMMETRY

  • WE GOT, WE ALWAYS GOT THE SAME

  • FILAMENT ORGANIZED THE SAME WAY.

  • HERE, THE RIGID AND THEY LINE UP

  • NEXT TO EACH OTHER AND DEFRACT

  • WELL.

  • HERE THEY FORM FOUR TWISTED

  • AROUND EACH OTHER.

  • HERE THEY MAKE A 10-STRANDED

  • CONDUIT TUBE AND DON'T REFRACT

  • TOO WELL.

  • BUT THEY ARE ALWAYS ASSEMBLED BY

  • THE SAME FIRST FACES.

  • SO, THAT'S STARTING TO GET

  • UNCANNY.

  • CRYSTALLIZE THE PROTEIN FOUR

  • TIMES AND MAYBE IF MAKES IT IS

  • SOMETHING IT WANTS TO DO.

  • SO IT FORMS A DIMER IN SOLUTION

  • AND EVERY TIME YOU CRYSTALLIZE A

  • FULL-LENGTH PROTEIN WE GET THE

  • SAME FILAMENT.

  • UNDER OTHER CIRCUMSTANCES, CUT

  • OFF THE C TERMINAL DOMAIN AND

  • FORM A RING AND THERE IS ONE

  • CRYSTAL STRUCTURE OF THAT.

  • SO, WHICH ONE OF THESE

  • ASSEMBLIES MAKE THE VIRAL MATRIX

  • OR DO NEITHER ONE OF THEM?

  • TO ANSWER THAT QUESTION WE MADE

  • MUTATIONS IN EACH INTERFACES

  • BECAUSE THIS ASSEMBLY AND THE

  • RING ASSEMBLY ARE BUILT BY

  • DIFFERENT SURFACES.

  • AMINO ACIDS THAT MAKE THIS

  • FILAMENT ON ARE THE OUTSIDE OF

  • THE RING AND AMINO BINDING RING

  • FORMATIONS ARE NOT WHAT

  • ASSEMBLED THIS FILAMENT.

  • SO LET ME SHOW YOU THE

  • MUTATIONS.

  • SO THIS IS THE DIMER INTERFACE.

  • YOU'RE LOOKING TOP DOWN AT THE

  • BUTTERFLY.

  • BLUE-BLUE.

  • LEUCIN 117 AND 112 ARE IMPORTANT

  • TO THE DIMER.

  • IF YOU MUTATE THEM, YOU GET

  • THIS.

  • SO THE WILDTYPE PROTEIN IS THE

  • DIMER.

  • MUTATE THE DIMER INTERFACE, YOU

  • GET MONOMER AND RING.

  • CAN YOU SEE THAT OR DO WE NEED

  • TO DIM THE LIGHTS MORE?

  • SO MUTATE THE DIMER INTERFACE

  • AND GET MONOMER AND RING.

  • IF YOU TRANSFECT CELLS AND NOW

  • WE ARE STANDING IN GREEN.

  • THE WILDTYPE PROTEIN TRAFFIC TO

  • THE CELL MEMBRANE AND BUDS OUT

  • THE FILAMENTOUS VIRUS LIKE

  • PARTS.

  • SO SOME LENGTH WISE IN MANY OF

  • THE CROSS SECTION.

  • THE MONOMER AND RING MUTATIONS

  • DON'T TRAFFIC AS WELL AS THE MEW

  • TAIN AND DON'T BUD ANYTHING AT

  • ALL.

  • SO THAT END-TO-END DIMER

  • INTERFACE IS IMPORTANT FOR

  • MATRIX ASSEMBLY AND BUDDING.

  • EVEN IF THE MUTANTS MAKE A RING.

  • HOW ABOUT THE FILAMENT WE KEEP

  • SEEING MADE BY PACKING SIDEWAYS

  • OF THE DIMERS?

  • THAT IS MADE BY THE C-C

  • INTERACTION.

  • SO IF THAT INTERFACE IS 214 AND

  • LOU SIN 307.

  • LET'S MUTATE THOSE.

  • WILDTYPE PROTEIN IS A DIMER.

  • THIS FIRST MEW SUBSTANT A DIMER.

  • WE EXPECTED THAT.

  • SO WE STILL HAVE THE DIMER.

  • THE WILDTYPE PROTEIN TRAFFIC TO

  • THE MEMBRANE AND BUDS OUT THE

  • VIRUS PARTICLES AND MAKES THESE

  • FUNNY RUFFLES.

  • WE DON'T KNOW WHAT THEY ARE.

  • THE WILDTYPE PROTEIN DOES THAT.

  • THIS MUTANT PROTEIN DOESN'T

  • TRAFFIC QUITE AS WELL BUT IT HAS

  • A CRAZY RUFFLING MORPHOLOGY.

  • IT DOESN'T BUD ANY PARTICLES BUT

  • MAKES A MEMBRANE WITH A FUNNY

  • RUFFLING EFFECT.

  • SO WE SAW THE STRUCTURE OF THE

  • MUTANT TO FIND OUT WHAT WAS

  • HAPPENING.

  • YOU HAVE THE SAME DIMER, THE

  • GREEN BUTTERFLY AND THE BLUE

  • BUTTERFLY.

  • BUT INSTEAD OF BEING PACKED

  • SIDE-BY-SIDE LIKE EVERY OTHER

  • CRYSTAL STRUCTURE, WE MUTATED

  • THAT INTERDAYS AND THEY ARE

  • TWISTED RELATIVE TO EACH OTHER.

  • SO IT MIGHT BE WHEN THEY TRAFFIC

  • TO THE MEMBRANE, THEY ARE MAKING

  • A FUNNY TWISTED FILAMENT MAKING

  • THAT RUFFLED MORPHOLOGY

  • THATICANT QUITE GET-TOGETHER AND

  • RELEASE THE VIRUS.

  • THIS OTHER MUTANT IS DIFFERENT.

  • IT DOESN'T MAKE DIMER.

  • IT ONLY MAKES RINGS.

  • AND THESE RINGS BIND RNA.

  • THE VP40 DIMER DOESN'T BIND RNA.

  • ONLY THE RING BIND RNA.

  • AND WE LOOKED AS THESE BY EM AND

  • THE SAME SIZE AND SHAPE BY THE

  • OTHER RINGS MADE BY DELETING THE

  • C TERMINUS.

  • THE RNA BINDING RINGS DO NOT

  • TRAFFIC TO THE MEMBRANE.

  • INSTEAD THEY HUG THE NUCLEUS AND

  • DON'T BUD ANYTHING AT ALL.

  • SO WHAT WE SEE FROM THOSE

  • EXPERIMENTS IS THAT DISRUPTING

  • THE INTERACTION THAT IS BUILD

  • THAT FILAMENT PREVENTS VIRUS

  • ASSEMBLY AND BUDDING EVEN IF

  • YOU'RE MAKING ONLY RINGS.

  • NOW LET'S BREAK THE RING.

  • THIS MUTATION WAS PREVIOUSLY

  • KNOWN AND PREVENTS RNA BINDING

  • AND RING FORMATION IT'S A DIMER.

  • IT TRAFFIC TO THE MEMBRANE.

  • IT BUDS OUT VIRUS-LIKE PARTICLES

  • AND THE SAME KIND OF MEMBRANE

  • RUFFLES AND LOOKS IDENTICAL TO

  • WILDTYPE AND ASSEMBLED AND BUDS.

  • SAME MOREOVERROLOGY AND NUMBER

  • OF PARTICLES.

  • YOU CAN'T TELL IT APART FROM

  • WILDTYPE.

  • WE CONCLUDE THAT SOMETHING ABOUT

  • THAT DIMER AND FILAMENT IS

  • INVOLVED IN VIRUS ASSEMBLY NOT

  • THE RING.

  • SO HOW DIFFERENT YOU THE DIMER

  • THAN THE RING?

  • THEY ARE PRETTY DIFFERENT.

  • SO EASY TO SEE HOW YOU'RE MAKING

  • THIS FILAMENT BY LENGTH WISE

  • ASSEMBLY OF THE DIMERS.

  • TO MAKE THE RING, YOU HAVE TO

  • SEPARATE THE NNC TERMINAL

  • DOMAINS FROM EACH OTHER, SPLIT

  • THEM APART, UNRALPH THE 70 AMINO

  • ACETATE MAKE THE INTERFACE AND

  • ROTATE THE DIMER FROM PARALLEL

  • TO ANTIPARALLEL AND BACKWARDS.

  • SO THEY ARE GOING TO REASSEMBLE

  • NOW BY THE GREEN INTERFACE THAT

  • USED TO BE HIDDEN BY THE C

  • TERMINAL DOMAIN.

  • AND THEN FOUR OF THESE

  • ANTIPARALLEL BACKWARDS DIMERS

  • MAKE THE RING AND THIS RING THEN

  • HAS AN RNA BINDING SITE IN THE

  • CENTER THAT WASN'T AVAILABLE FOR

  • THE FILAMENT.

  • SO WE THINK THIS IS SOMETHING TO

  • DO WITH THE VIRUS ASSEMBLY.

  • HOW?

  • THERE ARE THREE QUESTIONS YOU

  • MIGHT ASK YOURSELF.

  • THE FIRST ONE WOULD BE WHAT SIDE

  • OF THE THING INTERACTS WITH

  • MEMBRANE?

  • WELL, WE KNEW THAT THE

  • INTERACTION WITH MEMBRANE WAS

  • ELECTROSTATIC BECAUSE YOU COULD

  • SALT IT OFF.

  • SO, IF YOU LOOK FOR A BASIC

  • PATCH IN VP40, THERE IS REALLY

  • ONLY ONE AND THEY ARE ON THE

  • SAME SIDE OF THE FILAMENT.

  • IN THAT BASIC PATCH ARE FIVE

  • LYSINES CONSERVED ACROSS THE

  • EBOLA VIRUSES.

  • 4 OF THE 5 ARE ESSENTIAL FOR

  • MEMBRANE INTERACTION AND BUDDING

  • VIRUSES.

  • SO PROBABLY THIS SURFACE OF THE

  • FILAMENT IS THE ONE THAT

  • INTERACTS WITH MEMBRANE.

  • NEXT QUESTION YOU MIGHT ASK

  • YOURSELF IS, IS THIS IT?

  • IS THIS FILAMENT HOW YOU BUILD

  • THE FILAMENT VIRUS?

  • THERE ARE A LOT OF SATISFYING

  • THINGS ABOUT THIS MODEL.

  • ALL THE AIRPORT FACES WE THINK

  • ARE ESSENTIAL BECAUSE ANY TIME

  • YOU MUTATE THEM YOU NO LONGER

  • BUILD AND BUD A VIRUS.

  • BUT, THERE ARE TWO OTHER PIECES

  • OF INFORMATION THAT THIS MODEL

  • DOESN'T ADDRESS.

  • THE FIRST ONE IS THAT

  • INTERACTION WITH MEMBRANE

  • INDUCES A LIGMERRIZATION OF VP40

  • IN HEXAMERS AND BY OUR MODEL, WE

  • SEE 2, 4, 6, 8, 10, WITH NO JUMP

  • TO HEXAMER.

  • THE SECOND THING IS THAT

  • INTERACTION MEMBRANE SEEMS TO DO

  • SOME KIND OF CONFIRMATIONAL

  • CHANGE BETWEEN THE DOMAINS AND

  • THIS DIDN'T ANSWER THAT EITHER.

  • SO THE THIRD QUESTION WE ASKED

  • OURSELVES AND YOU MIGHT BE

  • ASKING YOURSELF RIGHT NOW, THERE

  • IS SOMETHING DIFFERENT HAPPENING

  • TO THIS STRUCTURE WHEN IT MAKES

  • IT ELECTROSTATIC INTERACTION

  • ACTION WITH MEMBRANE.

  • SO WE WENT THROUGH A SERIES OF

  • ATTEMPTS TO TRY TO SATISFY THE

  • POSITIVE CHARGE WITH THAT BASIC

  • PATCH.

  • NOW IT IS KNOWN THAT THIS IS A

  • NATURAL LIGAND OF VP40 IN THE

  • MEMBRANE AND A MOLECULE WILL

  • COMPETE.

  • SO WE SOAKED A LOT OF CRYSTALS

  • IN PHOSPHOR SEREIN.

  • WE TRIED TO CO-CRYSTALLIZE WITH

  • IT.

  • WE FOUND SUCCESS WITH DEXTRAN

  • SULPHATE.

  • IF WE INCUBATE AND GROW CRYSTALS

  • IN THE STRUCTURE, WHEN WE GET IS

  • THE A VP40 THAT IS NOW HEX MERIC

  • WITH N AND C SEPARATION.

  • SO LET ME WALK YOU THROUGH THIS

  • STRUCTURE.

  • THE N-TERMINAL DOMAINS ARE BLUE.

  • C ARE ORANGE.

  • THIS IS ONE MONOMER WITH THE

  • N-TERMINAL AND C TERMINAL

  • DOMAIN.

  • HERE ARE TWO MORE.

  • SO MOLECULES ONE-6 AND THE

  • HEXAMER.

  • THESE C TERMINAL DOMAINS ARE

  • STILL ATTACHED.

  • IF YOU RUN THE CRYSTAL AND

  • JELLY, THEY ARE THERE BUT WE

  • DON'T SEE THEM.

  • THEY HAVE SOMEHOW SPRUNG INTO

  • SOLVENT CHANNELS WHERE THEY

  • OCCUPY A LOT OF POSITIONS.

  • WE KNOW THEY ARE ATTACHED BUT WE

  • DON'T SEE THEM AND THEY BELONG

  • TO THESE AND WE CAN SEE WHICH

  • DIRECTION THEY ARE GOING FROM

  • THE POLYPEPTIDE CHAIN THAT

  • EXTEND.

  • THIS HEXAMERRIC BUILDING BLOCK

  • FORMS THIS FILAMENT IN THESE

  • CRYSTALS AND THIS IS ASSEMBLED 3

  • INTERFACES.

  • THE SAME DIMER INTERFACE

  • MUTATING BEFORE WITH THE SAME

  • LEUCIN 117 AND THE SAME C-C

  • INTERFACE WITH THE ORANGE ORANGE

  • THAT HAD THE SAME LEWISSINE AND

  • SOMETHING ELSE WE ARE CALLING

  • OLIGOMERIZATION INTERFACE

  • EXPOSED BOY THE RELEASE OF THE C

  • TERMINAL DOMAIN.

  • SO WE KNOW BY MUTAGENESIS THAT

  • EVERY INTERFACE, THIS REARRANGED

  • ZIGZAG FILAMENT IS ESSENTIAL FOR

  • BUDDING.

  • DOES THIS FILAMENT NOW FIT WHAT

  • WE KNOW ABOUT THE VIRUS?

  • THE EBOLA VIRUS LOOKS LIKE THIS

  • IN CROSS SECONDS.

  • WE HAVE A NUCLEO CAPSID AT THE

  • CENTER AND MEMBRANE ON THE

  • OUTSIDE AND THEN THE TOPOGRAPHY

  • TELLS US MULTIPLE PROTEIN LAYERS

  • BETWEEN THE NUCLEO CAPSID AND

  • THE MEMBRANE.

  • SO MATRIX HAS A LOT OF PROTEIN

  • LAYERS IN IT.

  • IF YOU LOOK AT THE RADIAL

  • DENSITY OF THE VIRUS INSIDE TO

  • OUT, YOU SEE A BIG PEEK FOR THE

  • NUCLEAR CAPSID AND A PEEK FOR

  • MEMBRANE.

  • WE CALL THIS INTERPEEK CENTRAL

  • PEEK AND OUTER PEEK IN THE

  • MEMBRANE.

  • HERE IS OUR ZIGZAG FILAMENT.

  • TURN IT ON ITS SIDE AND ROLE IT

  • OVER ONCE MORE, THERE ARE 3

  • PROTEIN LAYERS, INNER AND

  • CENTRAL AND OUTER LAYER.

  • THEY FIT TO SCALE WHAT WE KNOW

  • ABOUT THE WIDTH OF THE VEER YON,

  • ALWAYS FIXED, THE WIDTH OF THE

  • NUCLEO CAPSULE AND THE SPACE IN

  • BETWEEN AND THE DIMENSIONS OF

  • THE C TERMINAL AND N-TERMINAL

  • CORE AND THE REACH OF THESE.

  • THIS FITS THE BIOLOGY AS WELL.

  • WE KNOW FROM BIOLOGY THAT AS THE

  • C TERMINAL DOMAIN THAT BINDS

  • MEMBRANE.

  • WE ALSO KNOW THAT IT IS THE C

  • TERMINAL THAT BINDS NUCLEO CAPS

  • IN.

  • HOW CAN THIS HAPPEN UNLESS SOME

  • GO THIS WAY AND SOME GO THAT

  • WAY?

  • SO IT FITS WHAT WE UNDERSTAND

  • ABOUT THE VIRUS ASSEMBLY.

  • IT ALSO FITS THE SHAPE OF THE

  • VIRUS TOO.

  • SO HERE PROTEIN IS WHITE.

  • NOT PROTEIN IS BLACK.

  • WE ARE SHOO THETH INTO THE SIDE

  • OF THE EBOLA VIRUS AND THE

  • ZIGZAGGING FILAMENT SEEMS TO

  • FOLLOW THE CHECKER BOARD PATTERN

  • AND SCALE REPEATING DISTANCES.

  • SO WHAT WE HAVE EXPRESSED AS A

  • DIMER MAKES THIS FILAMENT

  • INTERMEDIATE AT THE MEMBRANE IT

  • SEEMS TO BE A REARRANGEMENT THAT

  • MAKES THIS BUILDING BLOCK.

  • THIS IS OUR CURRENT BEST MODEL

  • FOR HOW TO MAKE THIS ASSEMBLE.

  • UNDER SOME OTHER CIRCUMSTANCES,

  • SPLIT THE THING APART AND ROTATE

  • IT AND MAKE ANOTHER RING THAT

  • BINDS RNA.

  • WHAT IS THIS RING?

  • IS IT REAL?

  • REMEMBER THIS MUTATION.

  • PREVENT RNA BINDING AND RING

  • FORMATION?

  • IT RESULT IN NORMAL LOOKING

  • VIRUSES AND PERFECT SHAPES AND

  • PERFECT NUMBER.

  • THIS IS A LETHAL MUTATION.

  • YOU CAN NOT PROPAGATE AN EBOLA

  • VIRUS WITH THIS MUTATION.

  • WHY NOT?

  • YOU CAN STILL BUILD AND BUD A

  • VIRUS.

  • VIRUS CAN STILL ATTACHE CELL.

  • WHY IS THIS LETHAL?

  • THE RNA BINDING RING MUST DO

  • SOMETHING.

  • THAT'S WHAT WE CONCLUDE.

  • IT MUST DO SOMETHING ESSENTIAL

  • IN THE VIRUS LIFE CYCLE.

  • WHAT WOULD THAT BE?

  • THE RECENT DISCOVERY VP40 HAS A

  • SECOND FUNDS IN ADDITION TO

  • VIRUS ASSEMBLY AND BUDDING, VP40

  • EF CONTROLS VIRUS TRANSCRIPTION

  • INSIDE THE INFECTED CELLS.

  • MAYBE THIS IS WHAT THE RING IS

  • FOR.

  • IT'S THE OHMY STRUCTURE THAT

  • BIND RNA.

  • WE ONLIY SEE IT IN INFECTED

  • CELLS AND NEVER SEE THE RING AND

  • THE VIRUS.

  • NOW WE HAVE NEW TOOLS TO BRING

  • TO BEAR IN SITUATIONS.

  • WE FOUND POINT MUTATIONS THAT

  • MAKE ONLY RINGS AND THOSE THAT

  • NEVER MAKE RINGS.

  • SO WE PUT INTO A MINIGENOME

  • ASSAY.

  • WE HAVE THESE IN THE MIDDLE AND

  • THE WILDTYPE VP40 EXHIBITS

  • CONTROL FUNCTION AND THE VP40 WE

  • LOCKED INTO THAT RING CONTROLS

  • IT BETTER.

  • SO IF YOU ANCHOR IT INTO THE

  • RING YOU GET THE SAME FUNCTION.

  • IF YOU PREVENT VP40 FROM FORMING

  • THE RING, YOU GET LESS IT'S NOT

  • A TOTAL KNOCK OUT.

  • MAYBE TO BE IS MAKING PARTIAL

  • STRUCTURE.

  • SO THAT RING DOES SEEM TO HAVE

  • SOME KIND OF FUNCTION INSIDE THE

  • INFECTED CELL OF TRANSCRIPTIONAL

  • CONTROL.

  • SO THE WILDTYPE UNMODIFIED HERE

  • MAKES A DIMER.

  • THE DIMER IS CRITICAL FOR

  • TRAFFICKING TO THE MEMBRANE T

  • MAKES A FILAMENT TO BUILD AND

  • BUD A VIRUS AND MAKES AN RNA

  • BINDING TRICYCLE CONTROL THE

  • CELLS.

  • SO VP40 IS BOTH A STRUCTURAL AND

  • A NONSTRUCTURAL PROTEIN.

  • WE ARE DOING THIS ALL IN

  • BACTERIA SO WE DON'T NEED A

  • POSTTRANSLATIONAL MODIFICATION

  • TO DO IT.

  • MAYBE THERE IS ONE IN INFECTION.

  • THERE IS NO MUTATION AND THE

  • SAME POLYPEPTIDE MAKING

  • DIFFERENT FUNCTIONS FOR

  • DIFFERENT TIMES.

  • WHAT DO YOU CALL A PROTEIN THAT

  • DOES THAT?

  • WELL, WEATOID AROUND WITH

  • DIFFERENT NAMES BISTRUCTURAL,

  • AMBEE FORM, FINALLY WE DECIDED

  • THE TRANSFORMER WAS THE RIGHT

  • ANALOGY.

  • SO TRANSFORMERS ARE THESE TOY

  • THAT IS REFOLD FROM A ROBOT INTO

  • A VEHICLE.

  • TRUCK, CAR, IT'S NEVER A CUP OF

  • COFFEE OR AUGRAT BUT THEY REFOLD

  • FROM ONE TO ANOTHER.

  • WHAT I LIKE ABOUT THIS ANALOGY

  • IS YOU SEE THE SAME SECONDARY

  • STRUCTURAL ELEMENTS ACHIEVING

  • DIFFERENT ROLES IN THE DIFFERENT

  • MANIFESTATIONS.

  • SO FOR EXAMPLE, THE TIRES ARE

  • THE SEAT OF HIS PANTS AND HIS

  • ANKLES AND THE TIRES ARE OF

  • COURSE TIRES ON THE TRUCK.

  • IF YOU DID NOT KNOW THAT THIS

  • TRUCK EXISTED, I'M GOING BLOCK

  • IT OUT.

  • ALL YOU KNEW IS THE ROBOT AND

  • YOU KNEW THAT SOMETIMES THIS

  • PROTEIN COULD WALK AND TALK AND

  • SHOOT AND SOMETIMES THIS ROBOT

  • COULD CARRY A LOT OF CARGO AND

  • DRIVE FAST AND YOU NEEDED TO

  • FIND OUT WHY.

  • IT'S EASY TO SEE HOW THE TIRES

  • WOULD FLATTEN THE CARGO CARRYING

  • CAPACITY BUT IF YOU WERE JUST

  • LOOKING AT THIS, YOU WOULD

  • CONCLUDE THIS ROBOT HAD ROCKET

  • POWERED PANTS BECAUSE THEY ARE

  • ESSENTIAL FOR CARRYING A LOT OF

  • CARGO.

  • THE HEAD HERE IS THE HYDROPHOBIC

  • CORE ABOUT WHICH THE TRUCK IS

  • FOLDED.

  • SO IF YOU MUTATEED HEAD, YOU

  • KNOCKOUT EVERYTHING.

  • SO YOU SAY, THE HEAD IS THE

  • THINKING CENTER.

  • WE WERE NOT ALLOWED TO USE THAT

  • ANALOGY BECAUSE THE TOY COMPANY

  • WOULDN'T LET US AND SO INSTEAD,

  • WE CALLED IT MOLECULAR ORIGAMI.

  • AND SO, WHAT YOU CAN THINK ABOUT

  • IN THIS SITUATION IS THE PROTEIN

  • AS A BLANK SHEET OF THEY WERE

  • FOLDS INTO DIFFERENT STRUCTURES

  • ACCORDING TO DIFFERENT NEEDS AND

  • THE VIRUS LIFE CYCLE.

  • AND SO WE JUST SHOWED YOU HOW WE

  • THINK THE DIMER MAKES RNA

  • BINDING RING AND THE SAME ONE

  • REARRANGES TO MAKE THE HEXAMER

  • 2345 BUILDS AND BUDS THE VIRUS.

  • VIRUSES ARE COMPELLED BY

  • EVOLUTION TO BE SMALL.

  • ESPECIALLY RNA VIRUSES.

  • THEY DON'T VEY PROOF READING

  • MACHINERY.

  • YOU HAVE TO KEEP BELOW THAT

  • THRESHOLD.

  • HOW DO THEY KEEP THE GENOMES

  • LEAN AND MEAN?

  • HOW DO THEY DO MORE WITH LESS?

  • THEY CAN HIJACK HOST PROTEINS

  • FOR CENTRAL FUNCTIONS?

  • THEY CAN OVERLAP READING FRAMES.

  • THE SAME IN NUCLEIC ACID THAT

  • MAKES DIFFERENT PROTEINS.

  • THEY CAN HAVE MOONLIGHTING

  • PROTEINS FOR THE SAME PROTEIN

  • DOES DIFFERENT FUNCTIONS SO THE

  • NUCLEO CAPSID SUPRESSES

  • INTERFEAR ON SIGNALING.

  • THIS IS A FOURTH WHERE A VP40

  • CRYSTAL STRUCTURE AND HERE IS

  • ONE AND HERE IS ONE.

  • THE POLYPEPTIDE THAT THE GENE

  • ENCODES REARRANGE INTUSE

  • DIFFERENT STRUCTURES FOR

  • DIFFERENT FUNCTIONS AT DIFFERENT

  • TIMES TO GET MORE FUNCTION FROM

  • LESS GENE.

  • SO THIS IS WHAT WE BRING TO GO

  • TO THE VIRUS'S TERRITORY.

  • THIS IS WHAT IT BRINGS.

  • IT TRAVELS LIGHT.

  • BECAUSE THIS ACTUALLY, THE FEW

  • PROTEINS IT DOES MAKE, ACHIEVE A

  • MULTITUDE OF FUNCTIONS.

  • THIS IS MY LAB AT SCRIPPS.

  • WE COLLABORATE WITH A NUMBER OF

  • WONDERFUL LABS AND VERY

  • SUPPORTIVE.

  • ONE LAB DID THE VP40 AND THESE

  • GROUPS ARE WORKING WITH US TO

  • DEVELOP ANTIBODIES AGAINST THE

  • EBOLA VIRUS AND UNDERSTAND VIRAL

  • ENTRY AND I'D LIKE TO THANK THE

  • NIH FOR FUNDING ALSO THE SKAGGS

  • INSTITUTE FOR CHEMICAL BIOLOGY

  • AND I'D LIKE TO THANK YOU FOR

  • YOUR ATTENTION.

  • [ APPLAUSE ]

  • >> WHAT GREAT STORIES.

  • PLEASE, IF PEOPLE HAVE

  • QUESTIONS, THERE ARE MICROPHONES

  • IN THE AISLES.

  • FEEL FREE TO COME FORWARD AND

  • ASK WHAT IS ON YOUR MIND.

  • WHILE PEOPLE ARE THINKING, I

  • HAVE TO COME BACK TO SOMETHING

  • YOU SAID EARLY IN THE TALK ABOUT

  • THE DIFFERENCE IN WHO SURVIVES

  • EBOLA AND WHO DOESN'T IN TERMS

  • OF WHO IS ABLE TO MOUNT SOME

  • KIND OF AN IMMUNE RESPONSE IN

  • FOUR DAYS.

  • DO YOU HAVE ANY IDEA WHAT THAT

  • IS ABOUT?

  • WHAT DETERMINES WHETHER YOU'RE

  • IN THE SURVIVAL CATEGORY OR NOT?

  • >> WE DO NOT.

  • THERE ARE SOME OBVIOUS ANSWERS

  • THAT YOU CAN RULE OUT.

  • HEALTH CARE STATUS, NUTRITIONAL

  • STATUS.

  • IF YOU RULED THAT OUT, I THINK

  • WE STILL NEED TO DO THE WORK TO

  • UNDERSTAND.

  • I THINK THAT WE KNOW THAT THE

  • VIRAL FACTORS AT PLAY BUT WE

  • DON'T THE HUMAN GENETIC FACT

  • AUTHORITIES CONTROL EXISTENCE.

  • WE KNOW THESE FOR LASSA VIRUS.

  • EBOLA IS QUITE NEW.

  • LASSA IS QUITE OLD.

  • FOR EXAMPLE, LASSA VIRUS HAS

  • BEEN IN NIGERIA FOR THOUSANDS OF

  • YEARS AND SIERRA LEON 150 YEARS

  • AGO.

  • PEOPLE EVOLVED MUTATIONS IN

  • THEIR RECEPTOR LIKE A SICKLE

  • CELL ANEMIA SO THEY ARE LESS

  • SUSCEPTIBLE TO THE VIRUS.

  • EBOLA WE DON'T KNOW.

  • WE NEED PEOPLE ON THE GROUND TO

  • LOOK AT THE HUMAN GENETICS OF

  • THE SURVIVORS.

  • >> VERY INTERESTING TALK.

  • AND IN A DIFFERENT VERSION OF

  • QUESTION THAT DR. COLLINS ASKED,

  • MY QUESTION IS, DO WE KNOW --

  • YOU MENTIONED YOU DON'T KNOW BUT

  • THE THOUGHT IS, ARE YOU

  • IMPACTING DIFFERENT COMPOSITION

  • OF CELLS PERHAPS THE MUTANT

  • CELLS THAT CAN ACTUALLY

  • NEUTRALIZE?

  • OR IS THERE ANYTHING KNOWN ABOUT

  • THE PROFILE OF IMMUNOGLOBULIN

  • SYNTHESIS AND THE EFFECTED CELLS

  • THAT COULD EITHER NEUTRALIZE AND

  • PRODUCE IMMUNE RESPONSES, OR

  • THEY ARE NOT AFFECTED

  • IMMEDIATELY.

  • >> I DON'T THINK WE REALLY KNOW

  • THE ANSWERS TO THAT QUESTION YET

  • BECAUSE WE HAVEN'T DONE AS MUCH

  • IN-DEPTH ANALYSIS OF THE HUMAN

  • SURVIVORS AS WE NEED TO HAVE

  • DONE.

  • SO A LOT OF THE STUDIES ARE

  • ONGOING.

  • IT DOESN'T INFECT MOST CELL

  • TYPES, MONOCYTES AND MACROPHAGES

  • TO BEGIN.

  • SO IT'S QUITE A POLICE

  • OFFICERRIC VIRUS BUT WE HAVEN'T

  • LOOKED ENOUGH AT THE SURVIVORS

  • TO FIND OUT WHAT THE DIFFERENCE

  • IS IN THE CELL TYPES.

  • >> THE RING AND THE FILAMENT

  • THEY COEXIST.

  • SO, BASICALLY SOMETHING IS

  • DETERMINING THE FOLDING PATTERN.

  • DO YOU KNOW WHAT THAT IS?

  • IS IT A CHAPTER?

  • >> NO, AND IT'S KILLING ME.

  • WHAT IS THE TRIGGER?

  • WHAT MAKES IF DO ONE THING

  • AND -- SO I DON'T KNOW.

  • WE CAN SPECULATE.

  • SO, MAYBE AT SOME STAGE OF THE

  • VIRUS LIFE CYCLE THERE IS A LOT

  • OF VIRAL RNA AND WHAT I HAVE

  • DRAWN IS RNA BINDING AND DRAWING

  • A WEDGE BETWEEN THE DOMAINS AND

  • KICKING OFF THE C TERMINAL AND

  • OPENING UP.

  • IF IT'S NOT RNA, MAYBE IT'S A

  • PROTEIN COMPLEX LIKE A

  • POLYMERASE OR SOMETHING LIKE

  • THAT.

  • IS THERE A CHAPERON?

  • COULD BE.

  • WHAT WE ARE TRYING TO DO NOW IS

  • USE THESE POINT MUTATION THAT IS

  • WE HAVE THAT LOCK IT INTO ONLY

  • RING OR NEVER RING OR EITHER AND

  • SEE WHAT THEY PULL DOWN AND

  • BASED ON WHAT IT PULLS DOWN DOES

  • IT TELL US IF IT NEEDS A HOST

  • FACTOR TO DRIVE THOSE OR PURELY

  • A VIRAL FACTOR?

  • IS IT RNA?

  • AND RNA, WHICH RNA.

  • THE RN.

  • THAT PICKED OUT FROM THE CRYSTAL

  • STRUCTURE OF THE UGA, UGA, UGA.

  • SO DOES IT RECOGNIZE STOP

  • CODONS?

  • IS THAT WHAT IT IS TRYING TO

  • FIND?

  • DOES IT LOOK FOR THE END OF THE

  • GENE?

  • WE DON'T KNOW.

  • AND THOSE ARE EXACTLY THE KIND

  • OF QUESTIONS WE ARE TRYING TO

  • ASK.

  • ALSO WHAT IS THE THERMODYNAMICS?

  • ARE THESE ALL EQUALLY STABLE OR

  • DO YOU NEED THE INPUT OF ENERGY

  • OR CHAPERON IN ORDER TO GET FROM

  • ONE TO THE OTHER?

  • >> THERE IS A KINETICS

  • DIFFERENCE IN THE SYNTH US?

  • >> WE DON'T KNOW.

  • WE HAVE TRAFFICKED WHERE DP40 IS

  • AT DIFFERENT STAGES OF THE VIRUS

  • LIFE PSYCHE E8.

  • EARLY IT HUGS THE NUCLEUS AND

  • NEIGHBOR IS IN THE RING

  • FORMATION AND MAKING COPIES.

  • LATER IN THE VIRUS LIFE CYCLE,

  • IT CATCHES A RIDE ON

  • MICROTUBULES UP TO THE SURFACE

  • AND MAKES FILL COMMENTS BUDS

  • OUT.

  • SO THE LOCATION TRAFFIC MAY BE

  • WITH FUNCTION.

  • WHAT CAUSES IT TO MAKE THE

  • DIFFERENT STRUCTURES WE STILL

  • NEED TO FIGURE OUT.

  • BUT WHAT IS INTERESTING ABOUT

  • THAT IS IT IS A DIFFERENT

  • PERSPECTIVE ON THE PROTEIN

  • FOLDING PROBLEM, RIGHT 1234

  • INSTEAD OF UNKNOWN, UNFOLDED

  • THING TO ONE SINGLE FOLDED

  • STRUCTURE, WE HAVE A FOLDED AND

  • A FOLD ED AND THEY CONVERGE AND

  • ARE THESE EQUAL OR DIFFERENT OR

  • WHAT CAN WE LEARN ABOUT THE

  • PROTEIN FOLDING PROBLEM GETTING

  • FROM ONE TO THE OTHER?

  • CAN WE LEARN SOMETHING ABOUT

  • INFORMATION AND CODING THAT WE

  • HAVE MULTIPLE FUNCTIONS ENCODED

  • IN THIS ONE PIECE OF CODE.

  • >> SO, THE EXON NUCLEASE YOU

  • TALK ABOUT, ONE WOULD ENVISION

  • THAT IT MIGHT ACTUALLY DO HARM

  • TO THE REPLICATION OF THE VIRUS

  • TOO IF IT GET ACTIVATED IN AN

  • OPPORTUNE TIME.

  • IS THERE A TIMING INTERIM OF

  • WHEN THIS VIRAL ENCODED NUCLEUS

  • GET ACTIVATEED DURING THE LIFE

  • CYCLE SO IT ALLOWS IT TO EVADE

  • IMMUNE DETECTION BUT DOESN'T

  • HURT ITS OWN PRODUCTION?

  • >> THAT'S A FANTASTIC QUESTION.

  • THAT'S SOMETHING I WANTED TO ASK

  • EARLIER TODAY.

  • WE DON'T KNOW.

  • WE THAN ONE DOMAIN BIND GENOME

  • AND THE OTHER DOUBLE-STRANDED

  • RNA.

  • FOR THE PROTEIN TO FUNCTION THEY

  • MUST BE GENETICALLY LINKED.

  • SO THEY HAVE TO BE TETHERED

  • TOGETHER.

  • THE MP DOESN'T EXIST AS A

  • MONOMER, IT'S A LIGMER.

  • SO SOMEHOW, THIS INTERACTS WITH

  • THE FRIENDS.

  • SO, WE ALSO KNOW THAT THE LINKER

  • IS QUITE PATROLAISE SENSITIVE

  • AND IN INFECTION A LOT OF C

  • TERMINAL DOMAINS GO FREE.

  • IS THE THE C TERMINAL DOMAIN

  • GOING FREE THAT IS SCRUBBING OUT

  • DOUBLE-STRANDED NA OR IS THAT A

  • ACCIDENT OF CONTAMINATION?

  • OR THIS FUNCTION PHYSICALLY

  • TETHERED TO THE REP CALLS SIDE

  • OR TO ERASE SOME INTERMEDIATE AS

  • IT IS BEING MADE OR DOES IT HAVE

  • SOME OTHER FUNCTION THAT WE

  • NEVER THOUGHT ABOUT?

  • >> DOES IT DO ANY EDITING FOR

  • THE VIRAL GENOME ITSELF?

  • >> THAT IS ANOTHER QUESTION.

  • WE WANTED TO KEEP CYCLES OF

  • REPLICATION GOING TO SEE IF IT

  • HAD A PROOF READING FUNCTION.

  • WE DON'T KNOW.

  • WE LOVE TO DO THOSE KIND OF

  • STUDIES.

  • >> SO I HAVE A SECOND QUESTION

  • ABOUT THIS RNA BINDING TOWARDS

  • BY THE PROTEIN AT THE END AND

  • ALSO ON THE SIDE.

  • SO, I GUESS YOU MENTIONED THAT

  • CHEMICAL NATURE TOTALLY

  • DIFFERENT, SON HYDROPHOBIC AND

  • ONE IS ELECTROSTATIC.

  • WHICH DOMINANTS?

  • IF YOU ANALYZE THE BINDING

  • AFFINITY -- AUTOMOBILEY THE CAP

  • END BINDING HAS A DISADVANTAGE

  • BECAUSE IT NEEDS EACH STRAND TO

  • BIND TWO.

  • IF IT BIND ON THE SIDE YOU CAN

  • BIND MULTIPLE COPIES.

  • SO THERE IS ADVANTAGE AND

  • DISADVANTAGE IN THERE.

  • >> SO WE HAVEN'T -- WHAT WE HAVE

  • HAVE DONE AND HAVEN'T DONE IS HE

  • HOW IT BIND TO A CIRCULAR

  • DOUBLE-STRANDED RN.

  • THAT HEADS NO END.

  • WE SEE WHAT HAPPENS IS IT MAKES

  • THE CAP FIRST AND THEN THIS

  • BACKBONE BINDER DOES THE SAME

  • INTERACTION ALL THE WAY DOWN THE

  • REST.

  • SO IF YOU KEEP POLYMERIZING ONCE

  • IT HAS THIS CAP ON THERE.

  • MAR BERG VIRUS DOESN'T NEED THE

  • CAP AND IT IS HAPPY TO JUST

  • POLYMERASE.

  • SO, ANOTHER GROUP HAS BEEN DOING

  • SIMILAR INSTRUCT US AND THEY SAY

  • THE SAME THING.

  • STRUCTURES.

  • SO, BASED ON THAT, I WOULD SAY

  • IT IS THE BACKBONE BIND THEY'RE

  • MIGHT BE DOMINANT BUT WE HAVEN'T

  • BEEN ABLE TO TEASE THEM APART

  • YET.

  • YOU LOSE BINDING WHEN YOU HAVE

  • AN OVER HANG THAT PROJECTS INTO

  • THE SPACE THAT NEEDS TO BE

  • OCCUPIED BY THE END CAP.

  • SO, I DON'T KNOW WHAT THAT SAYS

  • ABOUT RELATIVE INFINITY BUT IT

  • SEEMS YOU NEED THE END CAP TO

  • GET IT GOING.

  • INFINITY IS NOT HIGH.

  • IT'S MAYBE 10 OR MAYBE A

  • MICROMOLAR.

  • >> ONE MORE QUESTION AND THEN WE

  • WILL ADJOURN TO THE RIBBON

  • CUTTING PLEASE.

  • >> IN THE CRUSTAL STRUCTURES OF

  • VP40, YOU SHOWED A HEX MERIC

  • RING I DIDN'T SEE LATER.

  • IS THAT INVOLVED IN THE CELL

  • DURING THE FASHION --

  • >> HEXAMER VERSUS OPT MER?

  • WE DON'T EVEN KNOW IF INFECTED

  • CELLS IT IS EVEN A COMPLETE RING

  • OR IF IT'S THE SAME INTERFACE

  • BUT SPLIT OPEN AND SPIRALING

  • AROUND THE NUCLEO CAPSID.

  • WE DON'T KNOW.

  • WE JUST KNOW THAT YOU CAN GET IT

  • TO FORM BOTH KIND OF RINGS AND

  • ONE CRYSTALIZED AND THE OTHER

  • DIDN'T.

  • >> ALL RIGHT.

  • >> WE WILL NOW INVITE EVERYBODY

  • TO WALK UP THE HALL TO THE

  • RIBBON CUTTING.

  • BEFORE YOU DO SO, PLEASE JOIN ME

  • IN THANKING ERICA FOR A REALLY

  • FASCINATING SEMINAR.

  • [ APPLAUSE ]

>> GOOD AFTERNOON, EVERYONE.

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