4np7

Structure of phosphotriesterase mutant (S308L/Y309A) from Agrobacterium radiobacter with diethyl thiophosphate bound in the active site

spinqualitylabelsall models 4np7, resolution 1.99Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4np7 is a 1 chain structure with sequence from Agrobacterium tumefaciens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.99Å Ligands: CO, DPJ, EDO, FE2, KCX Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q93LD7_RHIRD Publication Abstract from PubMed Phosphotriesterases (PTEs) have been isolated from a range of bacterial species, including Agrobcaterium radiobacter (PTEAr), and are efficient enzymes with broad substrate ranges. The turnover rate of PTEAr for the common organophosphorous insecticide malathion is lower than expected based on its physical properties; principally the pka of its leaving group. In this study, we rationalise the turnover rate of PTEAr for malathion using computational docking of the substrate into a high resolution crystal structure of the enzyme, suggesting that malathion is too large for the PTEAr binding pocket. Protein engineering through combinatorial active site saturation testing (CASTing) was then used to increase the rate of malathion turnover. Variants from a CASTing library in which Ser308 and Tyr309 were mutated yielded variants with increased activity towards malathion. The most active PTEAr variant carried Ser308Leu and Tyr309Ala substitutions, which resulted in a ca. 5000-fold increase in kcat/KM for malathion. X-ray crystal structures for the PTEAr Ser308Leu\Tyr309Ala variant demonstrate that the access to the binding pocket was enhanced by the replacement of the bulky Tyr309 residue with the smaller alanine residue. A 5000-fold increase in the specificity of a bacterial phosphotriesterase for malathion through combinatorial active site mutagenesis.,Naqvi T, Warden AC, French N, Sugrue E, Carr PD, Jackson CJ, Scott C PLoS One. 2014 Apr 10;9(4):e94177. doi: 10.1371/journal.pone.0094177. eCollection, 2014. PMID:24721933 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Phosphotriesterase 3D structures

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