1or0

Crystal Structures of Glutaryl 7-Aminocephalosporanic Acid Acylase: Insight into Autoproteolytic Activation

spinqualitylabelsall models 1or0, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1or0 is a 4 chain structure with sequence from Pseudomonas sp. SY-77-1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: EDO, MSE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function G7AC_PSEU7 Catalyzes the deacylation of 7 beta-(4-carboxybutanamido)cephalosporanic acid (glutaryl-7-aminocephalosporanic acid or GL-7-ACA) to 7-aminocephalosporanic acid (7-ACA). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Glutaryl 7-aminocephalosporanic acid acylase (GCA, EC 3.5.1.11) is a member of N-terminal nucleophile (Ntn) hydrolases. The native enzyme is an (alpha beta)(2) heterotetramer originated from an enzymatically inactive precursor of a single polypeptide. The activation of precursor GCA consists of primary and secondary autoproteolytic cleavages, generating a terminal residue with both a nucleophile and a base and releasing a nine amino acid spacer peptide. We have determined the crystal structures of the recombinant selenomethionyl native and S170A mutant precursor from Pseudomonas sp. strain GK16. Precursor activation is likely triggered by conformational constraints within the spacer peptide, probably inducing a peptide flip. Autoproteolytic site solvent molecules, which have been trapped in a hydrophobic environment by the spacer peptide, may play a role as a general base for nucleophilic attack. The activation results in building up a catalytic triad composed of Ser170/His192/Glu624. However, the triad is not linked to the usual hydroxyl but the free alpha-amino group of the N-terminal serine residue of the native GCA. Mutagenesis and structural data support the notion that the stabilization of a transient hydroxazolidine ring during autoproteolysis would be critical during the N --> O acyl shift. The autoproteolytic activation mechanism for GCA is described. Crystal structures of glutaryl 7-aminocephalosporanic acid acylase: insight into autoproteolytic activation.,Kim JK, Yang IS, Rhee S, Dauter Z, Lee YS, Park SS, Kim KH Biochemistry. 2003 Apr 15;42(14):4084-93. PMID:12680762 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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