(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 > Paraneoptera: NE > Hemiptera: NE > Prosorrhyncha: NE > Heteroptera: NE > Euheteroptera: NE > Neoheteroptera: NE > Panheteroptera: NE > Cimicomorpha: NE > Cimicoidea: NE > Cimicidae: NE > Cimex: NE > Cimex lectularius: 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 MWWLLVSTLLISVGSSSSEDNLVVDTDKGKVQGVTLKSATGKDVDAWLGI PFAKPPTGNLRFKLPQPPEKWDDTKQATRQPNSCVQTIDTTFGDFPGSNM WNANTDLSEDCLYLNVIVPKPRPTSNNKAPVMLYIFGGGFYCGSATLDVY DPKTLASEENVIVVSIQHRVASLGFLYLGTGEAPGNMGLFDQRMAMKWVK DNIQNFGGDPNKITLFGMSSGASSIGLHLMAPESHSLFNNAILESGTAFT PWTLMSKEENKKRGLDLAKQMKCTKDDNTHDISCLRSANATQMVYKEWEM ETKPSGVYEFPFVPVVDSQQPFFKTGESSGDNKFKKTGVIVGSNKEEGIY LLLYFLKDVLKKEEQTTVNEDQYKDAVEKIYPYLTEDNRRQIKDKYKTWQ GADKSNDYKDALDKMVGDSNITCSVNQFADVYAGLQQDVYVYLFDRISNV SPWPKWTGGMHGEETYYVFGEPLNATKGYSEADKKLSKEMMKYWANFART GDPNKDDKGQTTSVTWPKYDTTQKKYLKLAEKLEEGSKYREDQCTFWKTL GQHVSTNELDTSTSK
References
Title: Molecular and biochemical characterization of the bed bug salivary gland cholinesterase as an acetylcholine-sequestering enzyme Kim JH, Hwang CE, Yoon KA, Seong KM, Lee J, Lee SH Ref: Insect Biochemistry & Molecular Biology, 102:52, 2018 : PubMed
The common bed bug, Cimex lectularius, possesses a cholinesterase expressed exclusively in the salivary gland (ClSChE). In this study, we investigated the molecular forms, tissue distribution patterns and biochemical properties of ClSChE and showed that ClSChE exists as a soluble monomeric form or a soluble dimeric form connected by a disulfide bridge. Immunohistochemical analysis confirmed that ClSChE was expressed in the epithelial cells of both the salivary gland and the duct. In addition, the secretion of monomeric ClSChE through the proboscis during feeding was confirmed by western blotting using a ClSChE-specific antibody. To predict the role of ClSChE injected into the tissue of an animal host, we analyzed the extent of hydrolysis of acetylcholine (ACh) by ClSChE by ultra-performance liquid chromatography-tandem mass spectrometry. ClSChE binding to ACh was not clearly resolved in the binding assay format used in this study, probably due to the weak but detectable ACh-hydrolytic activity of ClSChE. Nevertheless, kinetic analysis revealed that ClSChE possesses extremely low Km (high affinity to ACh) and Vmax values. These findings suggest that ClSChE functions virtually as an ACh-sequestering protein by having a very strong affinity to ACh but an extremely long turnover time. Given that ACh regulates a wide variety of host physiologies, we discuss the tentative roles of ClSChE in blood vessel constriction and itch/pain regulation in the host.
Title: Identification and characterization of three cholinesterases from the common bed bug, Cimex lectularius Seong KM, Kim YH, Kwon DH, Lee SH Ref: Insect Molecular Biology, 21:149, 2012 : PubMed
We identified and characterized the full-length cDNA sequences encoding two acetylcholinesterases (ClAChE1 and ClAChE2) and a salivary gland-specific cholinesterase-like protein (ClSChE) from the common bed bug, Cimex lectularius. All three cholinesterase genes (Clac1, Clace2 and Clsce) have conserved motifs, including a catalytic triad, a choline-binding site and an acyl pocket. Phylogenetic analysis showed that ClAChE1 belongs to the insect AChE1 clade, whereas ClAChE2 belongs to the insect AChE2 clade. ClSChE was grouped into the clade containing all AChE1s, suggesting a paralogous relationship to ClAChE1. Transcription levels of Clace1 were higher than those of Clace2 in all tissues examined, including the central nervous system (CNS). In contrast, the Clsce transcript was not detected in the CNS but specifically found in the salivary gland at much higher levels (>3000-fold) than those of Clace1 and Clace2. Western blot analysis using anti-ClAChE antibodies, in conjunction with activity staining, revealed that ClAChE1 is more active than ClAChE2, whereas ClSChE has little enzyme activity. Three-dimensional structure modelling suggested that ClAChEs and ClSChE shared structural similarities, but had some differences in the residues forming the acyl pocket and oxyanion hole. The current findings should provide valuable insights into the evolution and functional diversification of insect cholinesterase.
