Smiley-9: Assembly and Egress Flashcards
What drives protein shell assembly?
protein-protein interactions
4 ways viruses overcome disadvantage of random collisions
- converted assembly
- assembly from polyproteins
- assisted assembly
- assembly at cellular membranes
What type pf capsid uses concerted assembly?
helical
example of virus that uses concerted assembly
tobacco mosaic virus (TMV)
Where does concerted assembly begin in TMV RNA genome?
pac signal or OAS (origin of assembly)
Sequential assembly definition
genome is inserted after the capsid is formed
What type of capsid uses sequential assembly?
icosahedral
What cleaves links between VP2 and VP3, and VP3 and VP1 in poliovirus
3CD protease
VP4-VP2 link in poliovirus is cut by?
autocatalytic RNA-dependent reaction during virion assembly
2 types of viral or cellular proteins that assist capsid assembly of large icosahedral viruses
- chaperones
- scaffolding proteins
Chaperone protein definition
proteins helping other proteins fold correctly by preventing non-specific associations
Where does capsid assembly occur in herpesvirus?
in the nucleus
Where does HIV assembly occur?
plasma membrane
Function of MA (matrix) in HIVs Gag polyprotein
target plasma membrane, anchors it via N-terminal myristic acid
Function of capsid (CA) in HIVs Gag polyprotein
forms core containing RNA genome
