Marshall SD

References (3)

Title : Biochemical characterisation of MdCXE1, a carboxylesterase from apple that is expressed during fruit ripening - Souleyre_2011_Phytochemistry_72_564
Author(s) : Souleyre EJ , Marshall SD , Oakeshott JG , Russell RJ , Plummer KM , Newcomb RD
Ref : Phytochemistry , 72 :564 , 2011
Abstract : Esters are an important component of apple (Malusxdomestica) flavour. Their biosynthesis increases in response to the ripening hormone ethylene, but their metabolism by carboxylesterases (CXEs) is poorly understood. We have identified 16 members of the CXE multigene family from the commercial apple cultivar, 'Royal Gala', that contain all the conserved features associated with CXE members of the alpha/beta hydrolase fold superfamily. The expression of two genes, MdCXE1 and MdCXE16 was characterised in an apple fruit development series and in a transgenic line of 'Royal Gala' (AO3) that is unable to synthesise ethylene in fruit. In wild-type MdCXE1 is expressed at low levels during early stages of fruit development, rising to a peak of expression in apple fruit at harvest maturity. It is not significantly up-regulated by ethylene in the skin of AO3 fruit. MdCXE16 is expressed constitutively in wild-type throughout fruit development, and is up-regulated by ethylene in skin of AO3 fruit. Semi-purified recombinant MdCXE1 was able to hydrolyse a range of 4-methyl umbelliferyl ester substrates that included those containing acyl moieties that are found in esters produced by apple fruit. Kinetic characterisation of MdCXE1 revealed that the enzyme could be inhibited by organophosphates and that its ability to hydrolyse esters showed increasing affinity (K(m)) but decreasing turnover (k(cat)) as substrate acyl carbon length increases from C2 to C16. Our results suggest that MdCXE1 may have an impact on apple flavour through its ability to hydrolyse relevant flavour esters in ripe apple fruit.
ESTHER : Souleyre_2011_Phytochemistry_72_564
PubMedSearch : Souleyre_2011_Phytochemistry_72_564
PubMedID: 21315388
Gene_locus related to this paper: 9rosa-CXE1 , 9rosa-CXE2 , 9rosa-CXE3 , 9rosa-CXE4 , 9rosa-CXE5 , 9rosa-CXE6 , 9rosa-CXE7 , 9rosa-CXE8 , 9rosa-CXE9 , 9rosa-CXE10 , 9rosa-CXE11 , 9rosa-CXE12

Title : High-resolution crystal structure of plant carboxylesterase AeCXE1, from Actinidia eriantha, and its complex with a high-affinity inhibitor paraoxon - Ileperuma_2007_Biochemistry_46_1851
Author(s) : Ileperuma NR , Marshall SD , Squire CJ , Baker HM , Oakeshott JG , Russell RJ , Plummer KM , Newcomb RD , Baker EN
Ref : Biochemistry , 46 :1851 , 2007
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 A resolution. The crystal structure revealed that AeCXE1 is a member of the alpha/beta-hydrolase fold superfamily, most closely related structurally to the hormone-sensitive lipase subgroup. The active site of the enzyme, located in an 11 A 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 muM) a more potent inhibitor than dimethylchlorophosphate (DMCP; IC50 = 9.2 muM). The structure of AeCXE1 with paraoxon bound was determined at 2.3 A 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.
ESTHER : Ileperuma_2007_Biochemistry_46_1851
PubMedSearch : Ileperuma_2007_Biochemistry_46_1851
PubMedID: 17256879
Gene_locus related to this paper: actde-CXE1

Title : The carboxylesterase gene family from Arabidopsis thaliana - Marshall_2003_J.Mol.Evol_57_487
Author(s) : Marshall SD , Putterill JJ , Plummer KM , Newcomb RD
Ref : Journal of Molecular Evolution , 57 :487 , 2003
Abstract : Carboxylesterases hydrolyze esters of short-chain fatty acids and have roles in animals ranging from signal transduction to xenobiotic detoxification. In plants, however, little is known of their roles. We have systematically mined the genome from the model plant Arabidopsis thaliana for carboxylesterase genes and studied their distribution in the genome and expression profile across a range of tissues. Twenty carboxylesterase genes (AtCXE) were identified. The AtCXE family shares conserved sequence motifs and secondary structure characteristics with carboxylesterases and other members of the larger alpha/beta hydrolase fold superfamily of enzymes. Phylogenetic analysis of the AtCXE genes together with other plant carboxylesterases distinguishes seven distinct clades, with an Arabidopsis thaliana gene represented in six of the seven clades. The AtCXE genes are widely distributed across the genome (present in four of five chromosomes), with the exception of three clusters of tandemly duplicated genes. Of the interchromosomal duplication events, two have been mediated through newly identified partial chromosomal duplication events that also include other genes surrounding the AtCXE loci. Eighteen of the 20 AtCXE genes are expressed over a broad range of tissues, while the remaining 2 (unrelated) genes are expressed only in the flowers and siliques. Finally, hypotheses for the functional roles of the AtCXE family members are presented based on the phylogenetic relationships with other plant carboxylesterases of known function, their expression profile, and knowledge of likely esterase substrates found in plants.
ESTHER : Marshall_2003_J.Mol.Evol_57_487
PubMedSearch : Marshall_2003_J.Mol.Evol_57_487
PubMedID: 14738307
Gene_locus related to this paper: 9rosa-CXE1 , 9rosa-CXE2 , 9rosa-CXE3 , 9rosa-CXE4 , 9rosa-CXE5 , 9rosa-CXE6 , 9rosa-CXE7 , 9rosa-CXE8 , 9rosa-CXE9 , 9rosa-CXE10 , 9rosa-CXE11 , 9rosa-CXE12 , actde-CXE1 , actde-CXE3 , actde-CXE4 , actde-CXE5 , actde-CXE6 , actde-CXE7 , actde-CXE8 , actde-CXE9 , actde-CXE10 , arath-At2g45610 , arath-AT2G03550 , arath-AT5G27320 , arath-AT5G62180 , arath-CXE12 , arath-CXE15 , arath-F1N13.220 , arath-F14J22.11 , arath-F14J22.12 , arath-F16N3.25 , arath-CXE8 , arath-At5g14310 , arath-CXE6 , arath-gid1 , arath-GID1B , arath-CXE11 , arath-CXE18 , arath-Q8LF34 , arath-CXE13 , arath-CXE1 , capan-PepEST , lyces-Q9ZWF3 , nicta-hsr203j , orysa-Q7XTC5 , orysa-Q852M6 , orysa-Q8GSE8 , orysa-Q8H5P9 , orysa-Q8H5P5 , orysa-Q8H5P4 , orysa-Q7F1Y5 , orysa-Q8GS14 , orysa-Q8GSJ3 , orysa-Q8GRZ3 , orysa-Q8H3K6 , orysa-Q8H3K4 , orysa-Q8RZ79 , orysa-Q93VD4 , orysa-Q94JD7 , pinra-PrMC3 , pissa-Q9SSY8 , vitvi-BIG8.1