Virus Structure Flashcards
Are all viruses based on icosahedral symmetry?
Many - BUT NOT ALL
What is the minimum number of capsid proteins?
60
Why can not many T=1 viruses infect alone?
limited to what you can package if only using 60 proteins to make container
have to break symmetry - proteins in capsid are not equivalent in position
What are coat protein dynamics?
can form diff reactions
different loop area form differently - trap in different conformations
What are MS2 coat protein conformations?
FG loop - A/B or C/C dimer
How is the Caspar and Klug’s theories of quasi-equivalence broken?
Herpes virus
Gemini virus - 2 capsids stuck together with a bit missing
papilloma - completely pentamers
HIV core - pentamers not evenly distributed forming a core
if a virus has 180 subunits is it always T=3?
NO
rhinovirus - 3 diff. proteins
MS2 - 1 protein folded in 3 diff. ways
How is poliovirus assembled?
VP0 into VP2 + VP4 when RNA is present and condensation around RNA genome
VP1 and VP3 stay assembled
empty 80S
Mature 160S
VP4 is internal - net inside capsid
How have VP1, VP2 and VP3 arise?
gene duplication
strand switching in replication complexes
How are some plant genomes packages separately?
Cowpea mosaic virus
segmented genome - 2RNAs separately packages
need an infection by multiple viruses
What are some types of complex viruses?
Blue tongue virus - T=13
What is the T=169 virus?
Michael Rossman
PBCV1 structure
has a portal
What are helical nucleocapsids?
Nucleic acids are wrapped up by protein sub units
How is SAR-CoV-2 structured?
genome similar to helical capsi
spike is main immunodominant region
Trimeric spike undergoes conformational change when cleaved
lipid binding picket on spike - antiviral binding agents can target this
