L11

Question 1

B-structure of amyloid fibres:

Answer 1

Cause cell and tissue damage in diseases such as CJD and Alzheimer’s.
Misfiled in can cause disease. Prion protein (PrP) becomes infectious as PrPc is converted to PrPsc. This is protease resistant due to formation of b-sheets which it doesn’t usually have.

Question 2

Chaperone:

Answer 2

Hydrophobic interior so lysozyme binds to this. ATP hydrolysed and when it binds there is a conformational change.
Like a molecular container - hydrophobic surface exposed when closed. when open, hydrophobic surfaces are hidden and hydrophilic on surface and is exposed.

Helps with protein folding. Not done randomly by trial and error but follows a protein folding pathway.

Question 3

BPTI:

Answer 3

Forms disulphides bridges with protein so slows down folding.

Question 4

Entropy of folding:

Answer 4

S=KlnW

Where w is the number of states/ confirmations. K is boltzmann’s constant.

Question 5

pKa and strength of acid and base:

Answer 5

The smaller the pKa then the stronger the acid and the weaker the conjugate base.