Antiviral

Question 1

can a virus reproduce on its own?

Answer 1

viruses cant reproduce they have to invade a host cell?

Question 2

how does a virus such a HIV get into the cell?

Answer 2

-the reverse transcriptase in the HIV can use its RNA

Question 3

what are some drug targets for HIV?

Answer 3

HIV Reverse transcriptase
HIV Integrase
HIV Protease

Question 4

what would the structure of a Nucleoside reverse transcriptase inhibitors be like?

Answer 4

nucleoside type molecules that looks like a natural substrate but lacks a 3 prime hydroxide and prevents the chain from elongating

Question 5

what would the structure of a Nucleoside reverse transcriptase inhibitors be like?

Answer 5

nucleoside type molecules that looks like a natural substrate but lacks a 3 prime hydroxide and prevents the chain from elongating
-its a DNA chain terminator

Question 6

what are some side effects for Nucleoside reverse transcriptase inhibitors?

Answer 6

Non-selective inhibition of mammalian DNA polymerases

Competing with natural nucleosides for cellular kinases

Question 7

what are some key infr about Nucleoside reverse transcriptase inhibitors?

Answer 7

Are not competitive inhibitors (with respect to nucleoside triphosphate substrates)
Bind to an allosteric binding site
Are reversible non-competitive inhibitors
Show a higher selectivity for HIVrt than nucleoside analogues

Question 8

what do HIV-protease inhibirotsdo?

Answer 8

Enzymatically liberates HIV-rt, HIV-integrase
and viral structural proteins from large nonfunctional poly-protein structures in the late
stages of the viral life cycle

Question 9

what does HIV-integrase inhibitors do?

Answer 9

HIV-integrase enzymatically splices the DNA
form of the HIV genome (ie. the DNA copy
produced by HIV –reverse transcriptase) into the
human DNA.
This way the virus utilises the host cell to copy
its DNA and also to translate it into copies of its
own proteins in order to replicate.

Question 10

what does HIV Fusion inhibitors do?

Answer 10

-binds to surface of the cell and prevents CD4 from binding
Structurally similar to HIV proteins responsible for the fusion of the virus to cell
membranes and subsequent intracellular uptake.
Enfuvirtide works by inhibiting HIV-1 fusion with CD4 cells.
Administered by injection

Question 11

what is the resisance taht can occur for the HIV fusion inhibitors?

Answer 11

mutations in
HIV’s GP-41 protein
prevent enfuvirtide
binding

Question 12

what is aciclovir?

Answer 12

its a drug and is a selective viral DNA polymerase inhibitor

for treatment of Herpes simplex 1 &2 infections

Question 13

how does aciclovir get activated and why is it selective

Answer 13

by the addition of the phosphate groups but can only be activated by viral thymidine kinase in infected cells

Question 14

what makes aciclovir poorly bioavaible?

Answer 14

• insoluble nucleoside but can be made more soluble by removing carboynl
• Xanthine oxidase reconverts to aciclovir in situ

Question 15

what is haemagglutinin?

Answer 15

Viral glycoprotein

binds to cell surface or cells contianing sialic acid

Question 16

what does Neuraminidase do?

Answer 16

Viral glycoprotein acting as an enzyme (a sialidase) Catalyses cleavage of terminal sugar molecule (sialic acid) from glycoproteins &
glycolipids

Question 17

how does HIV virus reproduce?

Answer 17

• the HIV virus which has glycoproteins on its surface membrane such GP140 that recognise the CD4 on a normal cell and bind to it
• the membrane of the virus fuse with the host cell and it enters the cell
• use HIV reverse transcriptase to use its own RNA to form double stranded DNA
• then an enzyme called intergrase catalyes the insertion of the HIV DNA into the DNA of the host cell
• now the virus can replicate, so its copied its RNA to transcribe the enzymes it needs to make polypeptides to then bud out with the surface membrane