ATP synthase delta/OSCP subunit explained

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 F_O complex with the F₁ complex. In mitochondria, the peripheral stalk consists of OSCP, as well as F_O components F6, B and D. In bacteria and chloroplasts the peripheral stalks have different subunit compositions: delta and two copies of F_O component B (bacteria), or delta and F_O components B and B' (chloroplasts).^[1]

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.^[2]

Human delta subunit of ATP synthase is coded by gene ATP5O.

Further reading

Wilkens . S. . Rodgers . A. . Ogilvie . I. . Capaldi . R. A. . Structure and arrangement of the delta subunit in the E. Coli ATP synthase (ECF1F0) . Biophysical Chemistry . 68 . 1–3 . 95–102 . 1997 . 9468613 . 10.1016/s0301-4622(97)00018-5.

Notes and References

1. Walker JE, Runswick MJ, Neuhaus D, Montgomery MG, Carbajo RJ, Kellas FA . Structure of the F1-binding domain of the stator of bovine F1Fo-ATPaseand how it binds an alpha-subunit . J. Mol. Biol. . 351 . 4 . 824–838 . 2005 . 16045926 . 10.1016/j.jmb.2005.06.012.
2. Dibrova . DV . Galperin . MY . Mulkidjanian . AY . Characterization of the N-ATPase, a distinct, laterally transferred Na+-translocating form of the bacterial F-type membrane ATPase. . Bioinformatics . 15 June 2010 . 26 . 12 . 1473–6 . 10.1093/bioinformatics/btq234 . 20472544. 2881411 .