(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Eukaryota: NE > Opisthokonta: NE > Metazoa: NE > Eumetazoa: NE > Bilateria: NE > Protostomia: NE > Ecdysozoa: NE > Panarthropoda: NE > Arthropoda: NE > Mandibulata: NE > Pancrustacea: NE > Hexapoda: NE > Insecta: NE > Dicondylia: NE > Pterygota: NE > Neoptera: NE > Holometabola: NE > Amphiesmenoptera: NE > Lepidoptera: NE > Glossata: NE > Neolepidoptera: NE > Heteroneura: NE > Ditrysia: NE > Obtectomera: NE > Noctuoidea: NE > Noctuidae: NE > Heliothinae: NE > Helicoverpa: NE > Helicoverpa armigera: NE
LegendThis sequence has been compared to family alignement (MSA) red => minority aminoacid blue => majority aminoacid color intensity => conservation rate title => sequence position(MSA position)aminoacid rate Catalytic site Catalytic site in the MSA MKWWTCVVFMCAAVLADDEWREVRTAQGPVRGRKHPTEDIYTFYNIPYAT APTGQDKFKAPLPPPVWLEPFDAVDEHVICPQPMFPGDLMPTNVVTKENC LIANVFVPNTKEKNLSVVVYVHGGAFIMGWGEMFKARQFMKTKDFIVVTF NYRLGIHGFLCLGTEDAPGNAGMKDQVALLRWVQKNIASFGGNPDDVTIA GYSAGSASVDLLMLSKSAEGLFHRVIPESGGNLAAFSIQRDPVEIAKSYA SKLGFDNGDDIYALGKFYMTAPIEKLTSDPFFDRTDSTFLFAPCVERETG DGAFLTESPLTILKTGNYRKLPVLYGFAEMEGLIRIDFFELWKHKMNEKF SDFLPADLKFDSEEEREEVANKIKEFYFGDKPVGNENILKYVDFFSDVIF AYPMLWAVKLHVEAGNNQVYLYEYSFVDEDVPVVPHTNIRGANHCAQTMA LSDGKNFTHHDDTLATPQFREMKKTIREIWHNFVKTGVPVPEGSWLPAWP AAGADRAPHMSLGERLELRGALLAERTRFWDDIYQRYYRDAVPPPTPPPR PRDEL
References
Title: Functional Characterization of two Carboxylesterase Genes Involved in Pyrethroid Detoxification in Helicoverpa armigera Li Y, Bai L, Zhao C, Xu J, Sun Z, Dong Y, Li D, Liu XL, Ma ZQ Ref: Journal of Agricultural and Food Chemistry, 68:3390, 2020 : PubMed
Insect carboxylesterases are major enzymes involved in metabolism of xenobiotics including insecticides. Two carboxylesterase genes, CarE001A and CarE001H, were cloned from the destructive agricultural pest Helicoverpa armigera. Quantitative Real-Time PCR showed that CarE001A and CarE001H were predominantly expressed in fat body and midgut, respectively; developmental expression analyses found that the expression levels of both CarEs were significantly higher in fifth- instar larvae than in other life stages. Recombinant CarE001A and CarE001H expressed in the Escherichia coli exhibited high enzymatic activity toward alpha-naphthyl acetate. Inhibition assays showed that organophosphates had strong inhibition on CarEs activity compared to pyrethroids. Metabolism assays indicated that CarE001A and CarE001H were able to metabolize beta-cypermethrin and lambda-cyhalothrin. Homology modeling and molecular docking analyses demonstrated that beta-cypermethrin could fit nicely into the active pocket of both carboxylesterases. These results suggested that CarE001A and CarE001H could play important roles in the detoxification of pyrehtroids in H. armigera.
Two mutations have been found in five closely related insect esterases (from four higher Diptera and a hymenopteran) which each confer organophosphate (OP) hydrolase activity on the enzyme and OP resistance on the insect. One mutation converts a Glycine to an Aspartate, and the other converts a Tryptophan to a Leucine in the enzymes' active site. One of the dipteran enzymes with the Leucine mutation also shows enhanced activity against pyrethroids. Introduction of the two mutations in vitro into eight esterases from six other widely separated insect groups has also been reported to increase substantially the OP hydrolase activity of most of them. These data suggest that the two mutations could contribute to OP, and possibly pyrethroid, resistance in a variety of insects. We therefore introduced them in vitro into eight Helicoverpa armigera esterases from a clade that has already been implicated in OP and pyrethroid resistance. We found that they do not generally enhance either OP or pyrethroid hydrolysis in these esterases but the Aspartate mutation did increase OP hydrolysis in one enzyme by about 14 fold and the Leucine mutation caused a 4-6 fold increase in activity (more in one case) of another three against some of the most insecticidal isomers of fenvalerate and cypermethrin. The Aspartate enzyme and one of the Leucine enzymes occur in regions of the H. armigera esterase isozyme profile that have been previously implicated in OP and pyrethroid resistance, respectively.
Some of the resistance of Helicoverpa armigera to conventional insecticides such as organophosphates and synthetic pyrethroids appears to be due to metabolic detoxification by carboxylesterases. To investigate the H. armigera carboxyl/cholinesterases, we created a data set of 39 putative paralogous H. armigera carboxyl/cholinesterase sequences from cDNA libraries and other sources. Phylogenetic analysis revealed a close relationship between these sequences and 70 carboxyl/cholinesterases from the recently sequenced genome of the silkworm, Bombyx mori, including several conserved clades of non-catalytic proteins. A juvenile hormone esterase candidate from H. armigera was identified, and B. mori orthologues were proposed for 31% of the sequences examined, however low similarity was found between lepidopteran sequences and esterases previously associated with insecticide resistance from other insect orders. A proteomic analysis of larval esterases then enabled us to match seven of the H. armigera carboxyl/cholinesterase sequences to specific esterase isozymes. All identified sequences were predicted to encode catalytically active carboxylesterases, including six proteins with N-terminal signal peptides and N-glycans, with two also containing C-terminal signals for glycosylphosphatidylinositol anchor attachment. Five of these sequences were matched to zones of activity on native PAGE at relative mobility values previously associated with insecticide resistance in this species.
