4 - Viral Structure Flashcards
1
Q
HIV-1 structural proteins
A
- RNA genome is diploid (2 identical copies)
- Nucleocapsid protects each RNA molecule
- Capsid encloses nucelocapsid, RNA and enzymes
2
Q
Function of structural proteins
A
- Protect the genome
- Deliver the genome
3
Q
Structural proteins protecting the genome
A
- A stable protein shell that protects genome
- Specific recognition and packaging of the genome
- Interaction with host cell membranes to form envelope
4
Q
Structural proteins delivering the genome
A
- Bind host cell receptors
- Uncoat the genome
- Fuse with cell membranes
- Transport genome to appropriate site
5
Q
HIV-1 invasion
A
- Assembly
- Budding via ESCRT
- Maturation
- Receptor attachment (CD4 and integrin)
- Entry receptor binding
- Fusion
6
Q
Proteins that HIV-1 encode for
A
Structural, accessory and regulatory
7
Q
Metastable
A
- Viruses must be stable, to protect the genome (not solid objects but instead vary in size and shape)
- Must be able to come apart on entry, to release the genome
8
Q
Icosahedron virus
A
- A solid with 20 triangular faces
- Each of the 20 faces is an equilateral triangle
- 5 fold symmetry
- The simplest icosahedron has 60 copies of the structural unit (3 protein subunits per triangular face)
- T number describes the number of subunits at each face
9
Q
5 fold symmetry
A
Five each of these triangles interact at each of 12 vertices
10
Q
Bigger viruses
A
- Have more subunits
- Capsid structure includes pentamers and hexamers
11
Q
Orthoreoviruses
A
Two capsids each with different structure
12
Q
IDP
A
Intrinsically disordered protein
13
Q
Herpesviruses
A
- Contain a tegument
- Tegument proteins fill the space between the nucleocapsid and the envelope
14
Q
Enveloped viruses
A
- Capsids covered by host membranes
- Envelope is lipid bilayer derived from cell as newly synthesized virus buds out of cell
- Viral E proteins are glycosylated in host cell during virus replication
15
Q
Nucleocapsid
A
The nucleic acid-protein assembly that is packaged within the virion
