Dorrian SJ

References (5)

Title : Genome sequence of the newly isolated chemolithoautotrophic Bradyrhizobiaceae strain SG-6C - Pearce_2011_J.Bacteriol_193_5057
Author(s) : Pearce SL , Pandey R , Dorrian SJ , Russell RJ , Oakeshott JG , Pandey G
Ref : Journal of Bacteriology , 193 :5057 , 2011
Abstract : Strain SG-6C (DSM 23264, CCM 7827) is a chemolithoautotrophic bacterium of the family Bradyrhizobiaceae. It can also grow heterotrophically under appropriate environmental conditions. Here we report the annotated genome sequence of this strain in a single 4.3-Mb circular scaffold.
ESTHER : Pearce_2011_J.Bacteriol_193_5057
PubMedSearch : Pearce_2011_J.Bacteriol_193_5057
PubMedID: 21742875

Title : Cloning and biochemical characterization of a novel carbendazim (methyl-1H-benzimidazol-2-ylcarbamate)-hydrolyzing esterase from the newly isolated Nocardioides sp. strain SG-4G and its potential for use in enzymatic bioremediation - Pandey_2010_Appl.Environ.Microbiol_76_2940
Author(s) : Pandey G , Dorrian SJ , Russell RJ , Brearley C , Kotsonis S , Oakeshott JG
Ref : Applied Environmental Microbiology , 76 :2940 , 2010
Abstract : A highly efficient carbendazim (methyl-1H-benzimidazol-2-ylcarbamate, or MBC)-mineralizing bacterium was isolated from enrichment cultures originating from MBC-contaminated soil samples. This bacterium, Nocardioides sp. strain SG-4G, hydrolyzed MBC to 2-aminobenzimidazole, which in turn was converted to the previously unknown metabolite 2-hydroxybenzimidazole. The initial steps of this novel metabolic pathway were confirmed by growth and enzyme assays and liquid chromatography-mass spectrometry (LC-MS) studies. The enzyme responsible for carrying out the first step was purified and subjected to N-terminal and internal peptide sequencing. The cognate gene, named mheI (for MBC-hydrolyzing enzyme), was cloned using a reverse genetics approach. The MheI enzyme was found to be a serine hydrolase of 242 amino acid residues. Its nearest known relative is an uncharacterized hypothetical protein with only 40% amino acid identity to it. Codon optimized mheI was heterologously expressed in Escherichia coli, and the His-tagged enzyme was purified and biochemically characterized. The enzyme has a K(m) and k(cat) of 6.1 muM and 170 min(-1), respectively, for MBC. Radiation-killed, freeze-dried SG-4G cells showed strong and stable MBC detoxification activity suitable for use in enzymatic bioremediation applications.
ESTHER : Pandey_2010_Appl.Environ.Microbiol_76_2940
PubMedSearch : Pandey_2010_Appl.Environ.Microbiol_76_2940
PubMedID: 20228105
Gene_locus related to this paper: 9acto-c8cp46

Title : Hydrolysis of pyrethroids by carboxylesterases from Lucilia cuprina and Drosophila melanogaster with active sites modified by in vitro mutagenesis - Heidari_2005_Insect.Biochem.Mol.Biol_35_597
Author(s) : Heidari R , Devonshire AL , Campbell BE , Dorrian SJ , Oakeshott JG , Russell RJ
Ref : Insect Biochemistry & Molecular Biology , 35 :597 , 2005
Abstract : The cloned genes encoding carboxylesterase E3 in the blowfly Lucilia cuprina and its orthologue in Drosophila melanogaster were expressed in Sf9 cells transfected with recombinant baculovirus. Resistance of L. cuprina to organophosphorus insecticides is due to mutations in the E3 gene that enhance the enzyme's ability to hydrolyse insecticides. Previous in vitro mutagenesis and expression of these modifications (G137D, in the oxyanion hole and W251L, in the acyl pocket) have confirmed their functional significance. We have systematically substituted these and nearby amino acids by others expected to affect the hydrolysis of pyrethroid insecticides. Most mutations of G137 markedly decreased pyrethroid hydrolysis. W251L was the most effective of five substitutions at this position. It increased activity with trans permethrin 10-fold, and the more insecticidal cis permethrin >130-fold, thereby decreasing the trans:cis hydrolysis ratio to only 2, compared with >25 in the wild-type enzyme. Other mutations near the bottom of the catalytic cleft generally enhanced pyrethroid hydrolysis, the most effective being F309L, also in the presumptive acyl binding pocket, which enhanced trans permethrin hydrolysis even more than W251L. In these assays with racemic 1RS cis and 1RS trans permethrin, two phases were apparent, one being much faster suggesting preferential hydrolysis of one enantiomer in each pair as found previously with other esterases. Complementary assays with individual enantiomers of deltamethrin and the dibromo analogue of cis permethrin showed that the wild type and most mutants showed a marked preference for the least insecticidal 1S configuration, but this was reversed by the F309L substitution. The W251L/F309L double mutant was best overall in hydrolysing the most insecticidal 1R cis isomers. The results are discussed in relation to likely steric effects on enzyme-substrate interactions, cross-resistance between pyrethroids and malathion, and the potential for bioremediation of pyrethroid residues.
ESTHER : Heidari_2005_Insect.Biochem.Mol.Biol_35_597
PubMedSearch : Heidari_2005_Insect.Biochem.Mol.Biol_35_597
PubMedID: 15857765
Gene_locus related to this paper: drome-EST23aes07 , luccu-E3aest7

Title : Hydrolysis of organophosphorus insecticides by in vitro modified carboxylesterase E3 from Lucilia cuprina - Heidari_2004_Insect.Biochem.Mol.Biol_34_353
Author(s) : Heidari R , Devonshire AL , Campbell BE , Bell KL , Dorrian SJ , Oakeshott JG , Russell RJ
Ref : Insect Biochemistry & Molecular Biology , 34 :353 , 2004
Abstract : Resistance of the blowfly, Lucilia cuprina, to organophosphorus (OP) insecticides is due to mutations in LcalphaE7, the gene encoding carboxylesterase E3, that enhance the enzyme's ability to hydrolyse insecticides. Two mutations occur naturally, G137D in the oxyanion hole of the esterase, and W251L in the acyl binding pocket. Previous in vitro mutagenesis and expression of these modifications to the cloned gene have confirmed their functional significance. G137D enhances hydrolysis of diethyl and dimethyl phosphates by 55- and 33-fold, respectively. W251L increases dimethyl phosphate hydrolysis similarly, but only 10-fold for the diethyl homolog; unlike G137D however, it also retains ability to hydrolyse carboxylesters in the leaving group of malathion (malathion carboxylesterase, MCE), conferring strong resistance to this compound. In the present work, we substituted these and nearby amino acids by others expected to affect the efficiency of the enzyme. Changing G137 to glutamate or histidine was less effective than aspartate in improving OP hydrolase activity and like G137D, it diminished MCE activity, primarily through increases in Km. Various substitutions of W251 to other smaller residues had a broadly similar effect to W251L on OP hydrolase and MCE activities, but at least two were quantitatively better in kinetic parameters relating to malathion resistance. One, W251G, which occurs naturally in a malathion resistant hymenopterous parasitoid, improved MCE activity more than 20-fold. Mutations at other sites near the bottom of the catalytic cleft generally diminished OP hydrolase and MCE activities but one, F309L, also yielded some improvements in OP hydrolase activities. The results are discussed in relation to likely steric effects on enzyme-substrate interactions and future evolution of this gene.
ESTHER : Heidari_2004_Insect.Biochem.Mol.Biol_34_353
PubMedSearch : Heidari_2004_Insect.Biochem.Mol.Biol_34_353
PubMedID: 15041019
Gene_locus related to this paper: luccu-E3aest7

Title : Developmental expression and gene\/enzyme identifications in the alpha esterase gene cluster of Drosophila melanogaster - Campbell_2003_Insect.Mol.Biol_12_459
Author(s) : Campbell PM , de QRGC , Court LN , Dorrian SJ , Russell RJ , Oakeshott JG
Ref : Insect Molecular Biology , 12 :459 , 2003
Abstract : Here we show how the 10 genes of the alpha esterase cluster of Drosophila melanogaster have diverged substantially in their expression profiles. Together with previously described sequence divergence this suggests substantial functional diversification. By peptide mass fingerprinting and in vitro gene expression we have also shown that two of the genes encode the isozymes EST9 (formerly ESTC) and EST23. EST9 is the major 'alpha staining' esterase in zymograms of gut tissues in feeding stages while orthologues of EST23 confer resistance to organophosphorus insecticides in other higher Diptera. The results for EST9 and EST23 concur with previous suggestions that the products of the alpha esterase cluster function in digestion and detoxification of xenobiotic esters. However, many of the other genes in the cluster show developmental or tissue-specific expression that seems inconsistent with such roles. Furthermore, there is generally poor correspondence between the mRNA expression patterns of the remaining eight genes and isozymes previously characterized by standard techniques of electrophoresis and staining, suggesting that the alpha cluster might only account for a small minority of the esterase isozyme profile.
ESTHER : Campbell_2003_Insect.Mol.Biol_12_459
PubMedSearch : Campbell_2003_Insect.Mol.Biol_12_459
PubMedID: 12974951