L13- protein folding Flashcards Preview

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Flashcards in L13- protein folding Deck (12):
1

What is the equation for Gibbs energy?

∆G=∆H-T∆S

2

For a reaction to proceed what must ∆G be?

Negative. So enthalpy decreases and entropy increases.

3

How can an increase in entropy be brought about?

By the displacement of water- increasing the randomness of water molecules.

4

When does hydrophobic collapse happen?

At the same time as formation of secondary structure.

5

What is the hydrophobic effect?

Non polar amino acid side chains associate with each other causing a polypeptide chain to collapse to a hydrophobic core.

6

What do H bonds do?

Contribute to cooperativity of folding

help stabilize secondary structures and native conformation ie tertiary and quaternary structure

7

Where do Van der Waals occur?

between non-polar side chains (and contribute to the stability of proteins)

8

Where do charge-charge interactions happen?

Between the oppositely charged side chanes in the interior of a protein - also stabilize the protein structure

9

What allows protein folding to happen in the crowded cell?

Molecular chaperones- by stabilising intermediates thereby minimising misfolding and aggregation. 

Optimises yield of correctly folded proteins.

10

Which classes of chaperones fold in th cytosol?

Hsp 70- which take it as soon as it.s coming out the ribosome

Hsp 60- like a barrel around it afterwards, then lets go to correctly folded protein

11

What does lack of cofactors lead to?

A build up of intermediates in the folding pathway

12

What can misfolding lead to?

Aggregation leading to toxicity