Is likely involved in the aerobic desaturation system responsible for the synthesis of oleic acid from stearoyl-CoA; oleic acid is a precursor of mycobacterial membrane phospholipids and triglycerides. Is the electron transfer partner for the stearoyl-CoA 9-desaturase DesA3. Catalyzes electron transfer reaction between NADPH and the diiron center of DesA3. Cannot use NADH. Binds 1 [2Fe-2S] cluster. Lipid metabolism; fatty acid metabolism. Interacts with DesA3 to form a functional acyl-CoA desaturase complex.