1d4o
From Proteopedia
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CRYSTAL STRUCTURE OF TRANSHYDROGENASE DOMAIN III AT 1.2 ANGSTROMS RESOLUTION
Overview
The 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.
About this Structure
1D4O is a Single protein structure of sequence from Bos taurus with as ligand. Active as NAD(P)(+) transhydrogenase (B-specific), with EC number 1.6.1.1 Full crystallographic information is available from OCA.
Reference
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
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