Question

When is GTP hydrolyzed between SRP and SRP-R?

A) During ribosome binding
B) During translocation through the translocon
C) During signal peptide cleavage
D) During ribosome exit from the ER

Answer 1

GTP hydrolysis between SRP and SRP-R occurs during ribosome binding.

Step-by-step explanation:

The hydrolysis of GTP between SRP and SRP-R occurs during ribosome binding. The SRP (signal recognition particle) binds to the hydrophobic signal peptide on the nascent polypeptide chain, causing translation elongation to pause. The SRP-ribosome complex then binds to an SRP receptor on the rough endoplasmic reticulum (RER) membrane, and GTP hydrolysis occurs during this binding process.