High-Resolution Crystal Structure of Plant Carboxylesterase AeCXE1, from Actinidia eriantha, and Its Complex with a High-Affinity Inhibitor Paraoxon

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dc.contributor.author Ileperuma, NR en
dc.contributor.author Marshall, SDG en
dc.contributor.author Squire, Christopher en
dc.contributor.author Baker, Heather en
dc.contributor.author Oakshott, JG en
dc.contributor.author Russell, RJ en
dc.contributor.author Plummer, KM en
dc.contributor.author Newcombe, RD en
dc.contributor.author Baker, Edward en
dc.date.accessioned 2016-08-10T00:28:06Z en
dc.date.issued 2007-02-20 en
dc.identifier.citation Biochemistry, 2007, 46(7), pp. 1851 - 1859 en
dc.identifier.issn 0006-2960 en
dc.identifier.uri http://hdl.handle.net/2292/29883 en
dc.description.abstract Carboxylesterases (CXEs) are widely distributed in plants, where they have been implicated in roles that include plant defense, plant development, and secondary metabolism. We have cloned, overexpressed, purified, and crystallized a carboxylesterase from the kiwifruit species Actinidia eriantha (AeCXE1). The structure of AeCXE1 was determined by X-ray crystallography at 1.4 Å resolution. The crystal structure revealed that AeCXE1 is a member of the α/β-hydrolase fold superfamily, most closely related structurally to the hormone-sensitive lipase subgroup. The active site of the enzyme, located in an 11 Å deep hydrophobic gorge, contains the conserved catalytic triad residues Ser169, Asp276, and His306. Kinetic analysis using artificial ester substrates showed that the enzyme can hydrolyze a range of carboxylester substrates with acyl groups ranging from C2 to C16, with a preference for butyryl moieties. This preference was supported by the discovery of a three-carbon acyl adduct bound to the active site Ser169 in the native structure. AeCXE1 was also found to be inhibited by organophosphates, with paraoxon (IC50 = 1.1 μM) a more potent inhibitor than dimethylchlorophosphate (DMCP; IC50 = 9.2 μM). The structure of AeCXE1 with paraoxon bound was determined at 2.3 Å resolution and revealed that the inhibitor binds covalently to the catalytic serine residue, with virtually no change in the structure of the enzyme. The structural information for AeCXE1 provides a basis for addressing the wider functional roles of carboxylesterases in plants. en
dc.description.uri http://pubs.acs.org/journal/bichaw en
dc.publisher American Chemical Society en
dc.relation.ispartofseries Biochemistry en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from http://www.sherpa.ac.uk/romeo/issn/0006-2960/ en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.title High-Resolution Crystal Structure of Plant Carboxylesterase AeCXE1, from Actinidia eriantha, and Its Complex with a High-Affinity Inhibitor Paraoxon en
dc.type Journal Article en
dc.identifier.doi 10.1021/bi062046w en
pubs.issue 7 en
pubs.begin-page 1851 en
pubs.volume 46 en
dc.rights.holder Copyright: American Chemical Society en
dc.identifier.pmid 17256879 en
pubs.author-url http://pubs.acs.org/doi/full/10.1021/bi062046w en
pubs.end-page 1859 en
pubs.publication-status Published en
dc.rights.accessrights http://purl.org/eprint/accessRights/RestrictedAccess en
pubs.subtype Article en
pubs.elements-id 73641 en
pubs.org-id Science en
pubs.org-id Biological Sciences en
pubs.org-id Science Research en
pubs.org-id Maurice Wilkins Centre (2010-2014) en
dc.identifier.eissn 1520-4995 en
pubs.record-created-at-source-date 2010-09-01 en
pubs.dimensions-id 17256879 en

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