3ia2

Pseudomonas fluorescens esterase complexed to the R-enantiomer of a sulfonate transition state analog

spinqualitylabelsall models 3ia2, resolution 1.65Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3ia2 is a 6 chain structure with sequence from Pseudomonas fluorescens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.65Å Ligands: GOL, J6Z, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ESTE_PSEFL Bifunctional enzyme, capable of both ester hydrolysis and halogenation. Has a low bromoperoxidase activity. Acts on many phenolic esters. 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 Acyl transfer is a key reaction in biosynthesis, including synthesis of antibiotics and polyesters. Although researchers have long recognized the similar protein fold and catalytic machinery in acyltransferases and hydrolases, the molecular basis for the different reactivity has been a long-standing mystery. By comparison of X-ray structures, we identified a different oxyanion-loop orientation in the active site. In esterases/lipases a carbonyl oxygen points toward the active site, whereas in acyltransferases a NH of the main-chain amide points toward the active site. Amino acid sequence comparisons alone cannot identify such a difference in the main-chain orientation. To identify how this difference might change the reaction mechanism, we solved the X-ray crystal structure of Pseudomonas fluorescens esterase containing a sulfonate transition-state analogue bound to the active-site serine. This structure mimics the transition state for the attack of water on the acyl-enzyme and shows a bridging water molecule between the carbonyl oxygen mentioned above and the sulfonyl oxygen that mimics the attacking water. A possible mechanistic role for this bridging water molecule is to position and activate the attacking water molecule in hydrolases, but to deactivate the attacking water molecule in acyl transferases. Different active-site loop orientation in serine hydrolases versus acyltransferases.,Jiang Y, Morley KL, Schrag JD, Kazlauskas RJ Chembiochem. 2011 Mar 21;12(5):768-76. doi: 10.1002/cbic.201000693. Epub, 2011 Feb 23. PMID:21351219 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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