eLA 6.1 Post-translational Modifications

Question 1

What is phosphorylation in post-translation modification?

Answer 1

Addition of negatively charged phosphoryl group to proteins

Question 2

What side chains does phosphorylation occur?

Answer 2

Hydroxyl side chains Serine, threonine and tyrosine

Question 3

What are phosphatases?

Answer 3

These carry out the removal of phosphate groups

Question 4

Where does methylation tend to occur?

Answer 4

On nucleophilic side chains such as lysine

Question 5

What is O-methylation?

Answer 5

This occurs on carboxylate side chains and results in the loss of a negative charge and increased hydrophobicity. It is also reversible

Question 6

What is the result of N-methylation?

Answer 6

It results in increased hydrophobicity

Question 7

Acetylation of N-terminal AAs is what?

Answer 7

Irreversible

Question 8

What is histone acetylation?

Answer 8

Addition of acetyl groups to lysine on histones. It leads to increased flexibility and increased gene transcription

Question 9

What is histone deacetylation?

Answer 9

It is decreased flexibility and decreased gene expression

Question 10

What are the three types of lipidation?

Answer 10

Myristoylation - addition of long FAs may act as handle to insert into PM
Palmitoylation - Reversible and affects association with specific membranes
Prenylation - Conserved sequences Caax