Proton translocation by transhydrogenase.
Transhydrogenase, in animal mitochondria and bacteria, couples hydride transfer between NADH and NADP(+) to proton translocation across a membrane. Within the protein, the redox reaction occurs at some distance from the proton translocation pathway and coupling is achieved through conformational changes. In an 'open' conformation of transhydrogenase, in which substrate nucleotides bind and product nucleotides dissociate, the dihydronicotinamide and nicotinamide rings are held apart to block hydride transfer; in an 'occluded' conformation, they are moved into apposition to permit the redox chemistry. In the two monomers of transhydrogenase, there is a reciprocating, out-of-phase alternation of these conformations during turnover.
Jackson
J Baz
JB
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. j.b.jackson@bham.ac.uk
D000818:Animals; D020134:Catalytic Domain; D017136:Ion Transport; D008958:Models, Molecular; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D009250:NADP Transhydrogenases / Q000737:chemistry* / Q000378:metabolism*; D010084:Oxidation-Reduction; D011485:Protein Binding; D011487:Protein Conformation; D017494:Proton Pumps / Q000737:chemistry* / Q000378:metabolism*; D018892:Proton-Motive Force; D011522:Protons
D017494:Proton Pumps; D011522:Protons; D009243:NAD; D009249:NADP; D009250:NADP Transhydrogenases