4fn4

short-chain NAD(H)-dependent dehydrogenase/reductase from Sulfolobus acidocaldarius

spinqualitylabelsall models 4fn4, resolution 1.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4fn4 is a 4 chain structure with sequence from Sulfolobus acidocaldarius DSM 639. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, NAD, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q4J9F2_SULAC Publication Abstract from PubMed The gene encoding a novel alcohol dehydrogenase that belongs to the short-chain dehydrogenases/reductases superfamily was identified in the aerobic thermoacidophilic crenarchaeon Sulfolobus acidocaldarius strain DSM 639. The saadh2 gene was heterologously overexpressed in Escherichia coli, and the resulting protein (SaADH2) was purified to homogeneity and both biochemically and structurally characterized. The crystal structure of the SaADH2 NADH-bound form reveals that the enzyme is a tetramer consisting of identical 27,024-Da subunits, each composed of 255 amino acids. The enzyme has remarkable thermophilicity and thermal stability, displaying activity at temperatures up to 80 degrees C and a 30-min half-inactivation temperature of approximately 88 degrees C. It also shows good tolerance to common organic solvents and a strict requirement for NAD(H) as the coenzyme. SaADH2 displays a preference for the reduction of alicyclic, bicyclic and aromatic ketones and alpha-ketoesters, but is poorly active on aliphatic, cyclic and aromatic alcohols, showing no activity on aldehydes. Interestingly, the enzyme catalyses the asymmetric reduction of benzil to (R)-benzoin with both excellent conversion (98 %) and optical purity (98 %) by way of an efficient in situ NADH-recycling system involving a second thermophilic ADH. The crystal structure of the binary complex SaADH2-NADH, determined at 1.75 A resolution, reveals details of the active site providing hints on the structural basis of the enzyme enantioselectivity. Biochemical and structural characterization of recombinant short-chain NAD(H)-dependent dehydrogenase/reductase from Sulfolobus acidocaldarius highly enantioselective on diaryl diketone benzil.,Pennacchio A, Sannino V, Sorrentino G, Rossi M, Raia CA, Esposito L Appl Microbiol Biotechnol. 2012 Jul 18. PMID:22805786 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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