10. Protein modification

Question 1

Where does most protein synthesis begin and what are the two exceptions?

Answer 1

Free cytosolic ribosomes

Mitochondria and plastids

Question 2

What causes Hsc70 to release the client protein?

Answer 2

NEF binds and removes ADP - ATP binds and Hsc 70 adopts open conformation and releases the client protein

Question 3

Name 3 different Hsc70 co-chaperones

Answer 3

NEFs e.g. BAG-1, BAG-2, HSPBP1
Hsp40 family members
CHIP (E3 Ub ligase)

Question 4

What does Hsp90 do?

Answer 4

Provide a platform for further protein folding and the assembly of multi-meric complexes

Question 5

What is chaperonin made up of and what does it do?

Answer 5

14 x Hsc60

Provides a cage to isolate small folding proteins from the cytosol

Question 6

what are the three activities of the 20S core particle of the proteasome?

Answer 6

chymotrypsin like
trypsin like
peptidylglutamyl-peptide hydrolysing