For a G protein to play its part in moving events forward in a signal pathway,
A) GDP must be released, and a GTP must occupy the nucleotide-binding site.
B) GTP must be released, and a GDP must occupy the nucleotide-binding site.
C) cGMP must occupy the otherwise empty nucleotide-binding site.
D) cGMP must leave the otherwise occupied nucleotide-binding site.
E) None of the above

Question

Quizplus · Accepted Answer

For a G protein to be activated, GDP must be released from the nucleotide-binding site, and a GTP molecule must occupy this site. This causes a conformational change in the G protein, allowing it to interact with downstream effector molecules and propagate the signal. Therefore, option A is the correct choice.

For a G Protein to Play Its Part in Moving