GTP Binding Proteins In Signalling

Question 1

What is GTP? Describe the structure

Answer 1

A nucleotide that makes up an RNA molecule. It is a ribose sugar which is attached to a guanine cyclic base on C1 of the sugar and a triphosphate on C4 of the sugar.

Question 2

What is GTP used for?

Answer 2

Protein synthesis as well as is involved in the dynamic instability of micro tubules on the cell. GTP can bind loosely to the beta-tubulin monomer of the tubular dimer and GTP hydrolysis can occur

Question 3

Describe the relationship between GTP and the tubular dimers in microtubules

Answer 3

There is one GTP bound to alpha tubulin and one bound to beta tubulin. The GTP bound to alpha tubulin is not hydrolysed but the GTP bound to beta tubulin is hydrolysed GDP

Question 4

Why is the GTP bound to beta-tubulin hydrolysed?

Answer 4

Energy released is required for the subunit disassembly from the microtubule. The GDP is then exchanged for GTP after reaction

Question 5

What is epinephrine?

Answer 5

A catecholamine produced by adrenal glands in the adrenal medulla that increases glycogen breakdown and the release of fatty acids (as well as the subsequent oxidation of fatty acids).

Question 6

How does epinephrine interact with its receptor?

Answer 6

It interacts with 15 amino acids on 4 transmembrane alpha helices