title: Crystal structure of cis-biphenyl-2,3-dihydrodiol-2,3-dehydrogenase from a PCB degrader at 2.0 A resolution.
abstract: cis-Biphenyl-2,3-dihydrodiol-2,3-dehydrogenase (BphB) is involved in the aerobic biodegradation of polychlorinated biphenyls (PCBs). The crystal structure of the NAD+-enzyme complex was determined by molecular replacement and refined to an R-value of 17.9% at 2.0 A. As a member of the short-chain alcohol dehydrogenase/reductase (SDR) family, the overall protein fold and positioning of the catalytic triad in BphB are very similar to those observed in other SDR enzymes, although small differences occur in the cofactor binding site. Modeling studies indicate that the substrate is bound in a deep hydrophobic cleft close to the nicotinamide moiety of the NAD+ cofactor. These studies further suggest that Asn143 is a key determinant of substrate specificity. A two-step reaction mechanism is proposed for cis-dihydrodiol dehydrogenases.
authors.affiliation: National Institute for Biotechnological Research (GBF), Department of Structure Research, Braunschweig, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hülsmeyer
authors.forename: H J
authors.initials: HJ
authors.lastname: Hecht
authors.forename: K
authors.initials: K
authors.lastname: Niefind
authors.forename: B
authors.initials: B
authors.lastname: Hofer
authors.forename: L D
authors.initials: LD
authors.lastname: Eltis
authors.forename: K N
authors.initials: KN
authors.lastname: Timmis
authors.forename: D
authors.initials: D
authors.lastname: Schomburg
mesh_terms: D001216:Asparagine; D001665:Binding Sites; D003460:Crystallization; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D046911:Macromolecular Substances; D008958:Models, Molecular; D009243:NAD / Q000378:metabolism; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D011078:Polychlorinated Biphenyls / Q000378:metabolism*; D017510:Protein Folding; D013379:Substrate Specificity
chemical_list: D046911:Macromolecular Substances; D009243:NAD; D001216:Asparagine; D011078:Polychlorinated Biphenyls; D010088:Oxidoreductases; C048338:trans-1,2-dihydrobenzene-1,2-diol dehydrogenase