title: Common origin of arthropod tyrosinase, arthropod hemocyanin, insect hexamerin, and dipteran arylphorin receptor.
abstract: Dipteran arylphorin receptors, insect hexamerins, cheliceratan and crustacean hemocyanins, and crustacean and insect tyrosinases display significant sequence similarities. We have undertaken a systematic comparison of primary and secondary structures of these proteins. On the basis of multiple sequence alignments the phylogeny of these proteins was investigated. Hexamerin subunits, hemocyanin subunits, and tyrosinases share extensive similarities throughout the entire amino acid sequence. Our studies suggest the origin of arthropod hemocyanins from ancient tyrosinase-like proteins. Insect hexamerins likely evolved from hemocyanins of ancient crustaceans, supporting the proposed sister-group position of these subphyla. Arylphorin receptors, responsible for incorporation of hexamerins into the larval fat body of diptera, are related to hexamerins, hemocyanins, and tyrosinase. The receptor sequences display extensive similarities to the first and third domains of hemocyanins and hexamerins. In the middle region only limited amino acid conservation was observed. Elements important for hexamer formation are deleted in the receptors. Phylogenetic analysis indicated that dipteran arylphorin receptors diverged from ancient hexamerins, probably early in insect evolution.
authors.affiliation: Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Burmester
authors.forename: K
authors.initials: K
authors.lastname: Scheller
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001181:Arthropods / Q000145:classification / Q000235:genetics*; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics*; D004156:Catechol Oxidase / Q000235:genetics; D003445:Crustacea / Q000235:genetics; D004175:Diptera / Q000235:genetics*; D004792:Enzyme Precursors / Q000235:genetics; D019143:Evolution, Molecular; D017344:Genes, Insect; D006433:Hemocyanins / Q000737:chemistry / Q000235:genetics*; D007301:Insect Hormones / Q000737:chemistry / Q000235:genetics*; D019476:Insect Proteins; D007313:Insecta / Q000235:genetics*; D008969:Molecular Sequence Data; D014442:Monophenol Monooxygenase / Q000737:chemistry / Q000235:genetics*; D005810:Multigene Family; D010802:Phylogeny; D011487:Protein Conformation; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D002352:Carrier Proteins; D004792:Enzyme Precursors; D007301:Insect Hormones; D019476:Insect Proteins; C092382:arylphorin-binding proteins, insect; C041137:storage proteins, Insecta; D006433:Hemocyanins; C038451:pro-phenoloxidase; D004156:Catechol Oxidase; D014442:Monophenol Monooxygenase