NAD(P) transhydrogenase (PTH) catalyzes the conversion of NADP and NADH to NADPH and NAD. The reaction is coupled with proton translocation across the cell membrane while the enzyme undergoes conformational change. PTH uses FAD as cofactor. PTH is composed of 3 domains.:
- Domain I binds NAD(+)/NADH.
- Domain II is a membrane-spanning domain.
- Domain III binds NADP(+)/NADPH.
PTH is composed of 2 subunits. Subunit beta contains domain III and part of II.
PTH domain III
1e3t – RrPTH domain III + NADP – Rhodospirillum rubrum - NMR
1pno – RrPTH domain III + NADP
1pnq – RrPTH domain III + NADPH
PTH domain I+III
1hzz, 1u28, 1u2d, 1xlt – RrPTH domain I+III + NADP + NAD
1nm5, 2fr8, 2fsv – RrPTH domain I+III (mutant) + NADP + NAD
1ptj, 1u2g, 2frd, 2oo5 – RrPTH domain I+III + NADP + NAD derivative
2oor – RrPTH domain I+III + NADP derivative + NAD
2bru – PTH domain I+III + NADP + NAD – Escherichia coli
