Coppin C

References (4)

Title : Structure and function of an insect alpha-carboxylesterase (alphaEsterase7) associated with insecticide resistance - Jackson_2013_Proc.Natl.Acad.Sci.U.S.A_110_10177
Author(s) : Jackson CJ , Liu JW , Carr PD , Younus F , Coppin C , Meirelles T , Lethier M , Pandey G , Ollis DL , Russell RJ , Weik M , Oakeshott JG
Ref : Proc Natl Acad Sci U S A , 110 :10177 , 2013
Abstract : Insect carboxylesterases from the alphaEsterase gene cluster, such as alphaE7 (also known as E3) from the Australian sheep blowfly Lucilia cuprina (LcalphaE7), play an important physiological role in lipid metabolism and are implicated in the detoxification of organophosphate (OP) insecticides. Despite the importance of OPs to agriculture and the spread of insect-borne diseases, the molecular basis for the ability of alpha-carboxylesterases to confer OP resistance to insects is poorly understood. In this work, we used laboratory evolution to increase the thermal stability of LcalphaE7, allowing its overexpression in Escherichia coli and structure determination. The crystal structure reveals a canonical alpha/beta-hydrolase fold that is very similar to the primary target of OPs (acetylcholinesterase) and a unique N-terminal alpha-helix that serves as a membrane anchor. Soaking of LcalphaE7 crystals in OPs led to the capture of a crystallographic snapshot of LcalphaE7 in its phosphorylated state, which allowed comparison with acetylcholinesterase and rationalization of its ability to protect insects against the effects of OPs. Finally, inspection of the active site of LcalphaE7 reveals an asymmetric and hydrophobic substrate binding cavity that is well-suited to fatty acid methyl esters, which are hydrolyzed by the enzyme with specificity constants ( approximately 10(6) M(-1) s(-1)) indicative of a natural substrate.
ESTHER : Jackson_2013_Proc.Natl.Acad.Sci.U.S.A_110_10177
PubMedSearch : Jackson_2013_Proc.Natl.Acad.Sci.U.S.A_110_10177
PubMedID: 23733941
Gene_locus related to this paper: luccu-E3aest7

Title : Birth and death of genes and functions in the beta-esterase cluster of Drosophila - Robin_2009_J.Mol.Evol_69_10
Author(s) : Robin C , Bardsley LM , Coppin C , Oakeshott JG
Ref : Journal of Molecular Evolution , 69 :10 , 2009
Abstract : Here we analyze the molecular evolution of the beta-esterase gene cluster in the Drosophila genus using the recently released genome sequences of 12 Drosophila species. Molecular evolution in this small cluster is noteworthy because it contains contrasting examples of the types and stages of loss of gene function. Specifically, missing orthologs, pseudogenes, and null alleles are all inferred. Phylogenetic analyses also suggest a minimum of 9 gene gain-loss events; however, the exact number and age of these events is confounded by interparalog recombination. A previous enigma, in which allozyme loci were mapped to beta-esterase genes that lacked catalytically essential amino acids, was resolved through the identification of neighbouring genes that contain the canonical catalytic residues and thus presumably encode the mapped allozymes. The originally identified genes are evolving with selective constraint, suggesting that they have a "noncatalytic" function. Curiously, 3 of the 4 paralogous beta-esterase genes in the D. ananassae genome sequence have single inactivating (frame-shift or nonsense) mutations. To determine whether these putatively inactivating mutations were fixed, we sequenced other D. ananassae alleles of these four loci. We did not find any of the 3 inactivating mutations of the sequenced strain in 12 other strains; however, other inactivating mutations were observed in the same 3 genes. This is reminiscent of the high frequency of null alleles observed in one of the beta-esterase genes (Est7/EstP) of D. melanogaster.
ESTHER : Robin_2009_J.Mol.Evol_69_10
PubMedSearch : Robin_2009_J.Mol.Evol_69_10
PubMedID: 19536450
Gene_locus related to this paper: droan-b3m7v2

Title : A genomics perspective on mutant aliesterases and metabolic resistance to organophosphates -
Author(s) : Claudianos C , Crone E , Coppin C , Russell R , Oakeshott JG
Ref : in Pesticide resistance , 2000

Title : An episode of accelerated amino acid change in Drosophila esterase-6 associated with a change in physiological function - Oakeshott_2000_Genetica_110_231
Author(s) : Oakeshott JG , van Papenrecht EA , Claudianos C , Morrish BC , Coppin C , Odgers WA
Ref : Genetica , 110 :231 , 2000
Abstract : In most lineages of the subgenus Sophophora esterase-6 is a homodimeric haemolymph protein In the melanogaster subgroup of species it has become a monomer which is mainly expressed in the male sperm ejaculatory duct Our analyses of esterase-6 sequences from three melanogaster subgroup species and two close relatives reveal a brief period of accelerated amino acid sequence change during the transition between the ancestral and derived states In this period of 2-6Myr the ratio of replacement to silent site substitutions 0.51 is about three times higher than the values in other lineages of the phylogeny There are about 50 more replacements in this period than would be predicted from the ratios of replacement to silent site substitutions found elsewhere in the phylogeny Modelling on the known structure of a related acetylcholinesterase suggests that an unusually high proportion of the replacements in the transitional branch are non-conservative changes on the protein surface Up to half the accelerated replacement rate can be accounted for by clusters of changes to the face of the molecule containing the opening of the active site gorge This includes changes in and around regions homologous to peripheral substrate binding sites in acetylcholinesterase There are also three changes in glycosylation status One region predicted to lie on the protein surface which becomes markedly more hydrophilic is proposed to be the ancestral dimerisation site that is lost in the transitional branch
ESTHER : Oakeshott_2000_Genetica_110_231
PubMedSearch : Oakeshott_2000_Genetica_110_231
PubMedID: 11766844
Gene_locus related to this paper: droer-EST6 , droer-q670j5 , droya-b4pga7 , droya-EST6