2og1

Crystal Structure of BphD, a C-C hydrolase from Burkholderia xenovorans LB400

spinqualitylabelsall models 2og1, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2og1 is a 2 chain structure with sequence from Burxl. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: EOH, GOL, SO4 Gene: bphD (BURXL) Activity: 2,6-dioxo-6-phenylhexa-3-enoate hydrolase, with EC number 3.7.1.8 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [BPHD_BURXL] Catalyzes an unusual C-C bond hydrolysis of 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid (HOPDA) to produce benzoic acid and 2-hydroxy-2,4-pentadienoic acid (HPD). 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 Kinetic and structural analyses of 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid (HOPDA) hydrolase from Burkholderia xenovorans LB400 (BphD(LB400)) provide insight into the catalytic mechanism of this unusual serine hydrolase. Single turnover stopped-flow analysis at 25 degrees C showed that the enzyme rapidly (1/tau(1) approximately 500 s(-1)) transforms HOPDA (lambda(max) = 434 nm) into a species with electronic absorption maxima at 473 and 492 nm. The absorbance of this enzyme-bound species (E:S) decayed in a biphasic manner (1/tau(2) = 54 s(-1), 1/tau(3) = 6 s(-1) approximately k(cat)) with simultaneous biphasic appearance (48 and 8 s(-1)) of an absorbance band at 270 nm characteristic of one of the products, 2-hydroxypenta-2,4-dienoic acid (HPD). Increasing solution viscosity with glycerol slowed 1/tau(1) and 1/tau(2) but affected neither 1/tau(3) nor k(cat), suggesting that 1/tau(2) may reflect diffusive HPD dissociation, and 1/tau(3) represents an intramolecular event. Product inhibition studies suggested that the other product, benzoate, is released after HPD. Contrary to studies in a related hydrolase, we found no evidence that ketonized HOPDA is partially released prior to hydrolysis, and, therefore, postulate that the biphasic kinetics reflect one of two mechanisms, pending assignment of E:S (lambda(max) = 492 nm). The crystal structures of the wild type, the S112C variant, and S112C incubated with HOPDA were each determined to 1.6 A resolution. The latter reveals interactions between conserved active site residues and the dienoate moiety of the substrate. Most notably, the catalytic residue His265 is hydrogen-bonded to the 2-hydroxy/oxo substituent of HOPDA, consistent with a role in catalyzing ketonization. The data are more consistent with an acyl-enzyme mechanism than with the formation of a gem-diol intermediate. Kinetic and structural insight into the mechanism of BphD, a C-C bond hydrolase from the biphenyl degradation pathway.,Horsman GP, Ke J, Dai S, Seah SY, Bolin JT, Eltis LD Biochemistry. 2006 Sep 19;45(37):11071-86. PMID:16964968 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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