- Source: ATP synthase delta/OSCP subunit
ATP synthase delta subunit is a subunit of bacterial and chloroplast F-ATPase/synthase. It is known as OSCP (oligomycin sensitivity conferral protein) in mitochondrial ATPase (note that in mitochondria there is a different delta subunit, ATP synthase delta/epsilon subunit).
The OSCP/delta subunit appears to be part of the peripheral stalk that holds the F1 complex α3β3 catalytic core stationary against the torque of the rotating central stalk, and links subunit A of the FO complex with the F1 complex. In mitochondria, the peripheral stalk consists of OSCP, as well as FO components F6, B and D. In bacteria and chloroplasts the peripheral stalks have different subunit compositions: delta and two copies of FO component B (bacteria), or delta and FO components B and B' (chloroplasts).
F-ATPases lacking this subunit generally transport sodium instead of protons. They are proposed to be called N-ATPases, since they seem to form a distinct group that is further apart from usual F-ATPases than A-ATPases are from V-ATPases.
Human delta subunit of ATP synthase is coded by gene ATP5O.
References
Further reading
Wilkens, S.; Rodgers, A.; Ogilvie, I.; Capaldi, R. A. (1997). "Structure and arrangement of the delta subunit in the E. Coli ATP synthase (ECF1F0)". Biophysical Chemistry. 68 (1–3): 95–102. doi:10.1016/s0301-4622(97)00018-5. PMID 9468613.
