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Flashcards in HIV life cycle Deck (12)
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1
Q

NINE phases of HIV life cycle

A

1) Attachment - attaches to T cells
2) Fusion - fuses membranes releasing capsid
3) Uncoating - releases ssRNA (2 single strands)
4) Reverse transcription - Make DNA copy
5) Integration - ds viral DNA inserted into chromosome
6) Replication - occurs in membrane
7) Assembly - new viriod
8) Budding
9) Maturation - infectious

2
Q

What does HIV infect

A

CD4+ T cells (produce cytokines and coordinate immune response)

3
Q

Structure of HIV

A

cytoplasmic cell of gp41 interacts with HIV matrix protein p17.

4
Q

What is a polypeptide precursor?

What are the 3 genes that code for these?

A

smaller proteins are generated by proteolytic cleavage. Allow for a more compact genome

1) GAG (group specific antigen, capsid and matrix)
2) POL (polymerase, reverse transcriptase, integrase)
3) ENV (envelope, gp120 and 41 attachment and fusion

5
Q

How is the capsid formed?

A

1000 repeats of the p24 capsid protein organised in hexameters, dimers and a few pentamers

6
Q

What tropism does HIV show

A

Initially infects macrophages (co-receptor CCR5) then changes to CD4+ cells (CXCR4)

7
Q

How does the virus attach

A

Conformational change bends gp41 so its inserted into the membrane, brings them together. gp120 allows interaction with co-receptor

8
Q

How does Enfuvirtide work?

A

Inhibits fusion process and prevents virus from entering cell, biomimetic peptide.

9
Q

What are the THREE entry inhibitors?

A

1) gp120-CD4 binding - ibalizumab
2) gp120-co-receptor binding - maraviroc
3) gp41-mediated membrane fusion - enfuviritide

10
Q

How does Raltegravir work?

A

Blocks active site not integrated into chromosome, targets integrate viral DNA complex in the PIC

11
Q

GAG polyprotein

1) what does it do

A

cleavage by HIV protease results in release of matrix protein, capsid protein, protein NC and p6 (which plays a role in the initiation of budding)

12
Q

Protease inhibitors

1) What is the structure of HIV-protease 1
2) Give an example

A

1) 99 aino acid homodimeric aspartyl protease

2) saquinavir - not cleaved by protease so they remain in the active site and block it