Certain cysteine-containing proteins of the mitochondrial intermembrane space are imported from the cytosol with the help of the Mia40 protein via a disulfide relay system. What drives the unidirectional import of these proteins? Are these proteins reduced or oxidized at their cysteine residues upon import?
A) ATP hydrolysis; oxidized
B) The electron-transport chain; oxidized
C) ATP hydrolysis; neither oxidized nor reduced
D) ATP hydrolysis; reduced
E) The electron-transport chain; reduced

Question

Quizplus · Accepted Answer

Oxidation of the imported proteins creates reduced Mia40, which ultimately donates its electrons to the electron-transport chain to reset to its oxidized form for another round of import.

Certain Cysteine-Containing Proteins of the Mitochondrial Intermembrane Space Are Imported