2c7b

The Crystal Structure of EstE1, a New Thermophilic and Thermostable Carboxylesterase Cloned from a Metagenomic Library

spinqualitylabelsall models 2c7b, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2c7b is a 2 chain structure with sequence from Uncultured archaeon. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.3Å Ligands: MSE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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 BACKGROUND: EstE1 is a hyperthermophilic esterase belonging to the hormone-sensitive lipase family and was originally isolated by functional screening of a metagenomic library constructed from a thermal environmental sample. Dimers and oligomers may have been evolutionally selected in thermophiles because intersubunit interactions can confer thermostability on the proteins. The molecular mechanisms of thermostabilization of this extremely thermostable esterase are not well understood due to the lack of structural information. RESULTS: Here we report for the first time the 2.1-A resolution crystal structure of EstE1. The three-dimensional structure of EstE1 exhibits a classic alpha/beta hydrolase fold with a central parallel-stranded beta sheet surrounded by alpha helices on both sides. The residues Ser154, Asp251, and His281 form the catalytic triad motif commonly found in other alpha/beta hydrolases. EstE1 exists as a dimer that is formed by hydrophobic interactions and salt bridges. Circular dichroism spectroscopy and heat inactivation kinetic analysis of EstE1 mutants, which were generated by structure-based site-directed mutagenesis of amino acid residues participating in EstE1 dimerization, revealed that hydrophobic interactions through Val274 and Phe276 on the beta8 strand of each monomer play a major role in the dimerization of EstE1. In contrast, the intermolecular salt bridges contribute less significantly to the dimerization and thermostability of EstE1. CONCLUSION: Our results suggest that intermolecular hydrophobic interactions are essential for the hyperthermostability of EstE1. The molecular mechanism that allows EstE1 to endure high temperature will provide guideline for rational design of a thermostable esterase/lipase using the lipolytic enzymes showing structural similarity to EstE1. Crystal structure of hyperthermophilic esterase EstE1 and the relationship between its dimerization and thermostability properties.,Byun JS, Rhee JK, Kim ND, Yoon J, Kim DU, Koh E, Oh JW, Cho HS BMC Struct Biol. 2007 Jul 12;7:47. PMID:17625021 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Carboxylesterase 3D structures

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