Alternate quinone coupling in a new class of succinate dehydrogenase may potentiate mycobacterial respiratory control.

There is a paucity of information on the unique components that pathogens use to form respiratory chains. It is not known why mycobacteria encode multiple succinate dehydrogenases (SDHs) to perform menaquinone-linked succinate oxidation, a thermodynamically unfavorable reaction (ΔG° = +21 kJ·mol ). In other bacteria, specific di-heme SDHs overcome this using the proton motive force.