1d4o | pdb_00001d4o
CRYSTAL STRUCTURE OF TRANSHYDROGENASE DOMAIN III AT 1.2 ANGSTROMS RESOLUTION
Structural highlights
Function[NNTM_BOVIN] The transhydrogenation between NADH and NADP is coupled to respiration and ATP hydrolysis and functions as a proton pump across the membrane. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe nicotinamide nucleotide transhydrogenases (TH) of mitochondria and bacteria are membrane-intercalated proton pumps that transduce substrate binding energy and protonmotive force via protein conformational changes. In mitochondria, TH utilizes protonmotive force to promote direct hydride ion transfer from NADH to NADP, which are bound at the distinct extramembranous domains I and III, respectively. Domain II is the membrane-intercalated domain and contains the enzyme's proton channel. This paper describes the crystal structure of the NADP(H) binding domain III of bovine TH at 1.2 A resolution. The structure reveals that NADP is bound in a manner inverted from that previously observed for nucleotide binding folds. The non-classical binding mode exposes the NADP(H) nicotinamide ring for direct contact with NAD(H) in domain I, in accord with biochemical data. The surface of domain III surrounding the exposed nicotinamide is comprised of conserved residues presumed to form the interface with domain I during hydride ion transfer. Further, an adjacent region contains a number of acidic residues, forming a surface with negative electrostatic potential which may interact with extramembranous loops of domain II. Together, the distinctive surface features allow mechanistic considerations regarding the NADP(H)-promoted conformation changes that are involved in the interactions of domain III with domains I and II for hydride ion transfer and proton translocation. Crystal structure of transhydrogenase domain III at 1.2 A resolution.,Prasad GS, Sridhar V, Yamaguchi M, Hatefi Y, Stout CD Nat Struct Biol. 1999 Dec;6(12):1126-31. PMID:10581554[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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