title: A novel variant of the catalytic triad in the Streptomyces scabies esterase.
abstract: The crystal structure of a novel esterase from Streptomyces scabies, a causal agent of the potato scab disease, was solved at 2.1 A resolution. The tertiary fold of the enzyme is substantially different from that of the alpha/beta hydrolase family and unique among all known hydrolases. The active site contains a dyad of Ser 14 and His 283, closely resembling two of the three components of typical Ser-His-Asp(Glu) triads from other serine hydrolases. Proper orientation of the active site imidazol is maintained by a hydrogen bond between the N delta-H group and a main chain oxygen. Thus, the enzyme constitutes the first known natural variation of the chymotrypsin-like triad in which a carboxylic acid is replaced by a neutral hydrogen-bond acceptor.
authors.affiliation: Medical Research Council of Canada Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton.
authors.forename: Y
authors.initials: Y
authors.lastname: Wei
authors.forename: J L
authors.initials: JL
authors.lastname: Schottel
authors.forename: U
authors.initials: U
authors.lastname: Derewenda
authors.forename: L
authors.initials: L
authors.lastname: Swenson
authors.forename: S
authors.initials: S
authors.lastname: Patkar
authors.forename: Z S
authors.initials: ZS
authors.lastname: Derewenda
mesh_terms: D000595:Amino Acid Sequence; D017151:Antibodies, Catalytic / Q000737:chemistry; D001665:Binding Sites; D004950:Esterases / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D014644:Genetic Variation; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics / Q000276:immunology; D014867:Water / Q000737:chemistry
chemical_list: D017151:Antibodies, Catalytic; D014867:Water; D004950:Esterases