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).

[2] 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.

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

"Structure and arrangement of the delta subunit in the E. Coli ATP synthase (ECF1F0)".