2yz7
X-ray analyses of 3-hydroxybutyrate dehydrogenase from Alcaligenes faecalis
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedD-3-Hydroxybutyrate dehydrogenase, which catalyzes the reversible reaction between D-3-hydroxybutyrate and acetoacetate, has been classified into the short-chain dehydrogenase/reductase family and is a useful marker in the assay of diabetes mellitus and/or ketoacidosis. The enzyme from Alcaligenes faecalis was crystallized in the apo form and in the holo form with acetate as a substrate analogue. The crystal structures of both forms were determined at 2.2 angstroms resolution. The enzyme is a tetramer composed of four subunits assembled with noncrystallographic 222 point symmetry. Each subunit has two domains. The principal domain adopts the Rossmann fold essential for nucleotide binding, which is a common feature of the SDR family. NAD+ is bound in a large cleft in the domain. The pyrophosphate group of NAD+ is covered by the small additional domain, which is supported by two extended arms allowing domain movement. In the catalytic site, a water molecule is trapped by the catalytic Tyr155 and Ser142 residues in the vicinity of the bound NAD+ and acetate. The substrate analogue acetate is bound above the nicotinamide plane. A substrate (D-3-hydroxybutylate) bound model can reasonably be constructed by adding two C atoms into the void space between the water O atom and the methyl group of the acetate, suggesting a substrate-bound state before enzymatic reaction occurs. Based on these structural features, a reaction mechanism has been proposed. The structures of Alcaligenes faecalis D-3-hydroxybutyrate dehydrogenase before and after NAD+ and acetate binding suggest a dynamical reaction mechanism as a member of the SDR family.,Hoque MM, Shimizu S, Hossain MT, Yamamoto T, Imamura S, Suzuki K, Tsunoda M, Amano H, Sekiguchi T, Takenaka A Acta Crystallogr D Biol Crystallogr. 2008 May;64(Pt 5):496-505. Epub 2008, Apr 19. PMID:18453685[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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