Primary Structure of a Member of the Serpin Superfamily of Proteinase Inhibitors from an Insect, Manduca sexta

• Published in: The Journal of biological chemistry Vol. 264; no. 2; pp. 965 - 972
• Main Authors: Kanost, M R, Prasad, S V, Wells, M A
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 15.01.1989; American Society for Biochemistry and Molecular Biology
• Subjects: ADN; Amino Acid Sequence; Animals; Base Sequence; Biological and medical sciences; Biotechnology; Cloning, Molecular; DNA; DNA - genetics; ENZYME INHIBITORS; FAT BODY; Fundamental and applied biological sciences. Psychology; Genes. Genome; Genetic engineering; Genetic technics; GLICOPROTEINAS; GLYCOPROTEINE; GLYCOPROTEINS; HAEMOLYMPH; HEMOLINFA; HEMOLYMPHE; INHIBIDORES DE ENZIMAS; INHIBITEUR D'ENZYME; Lepidoptera; Lepidoptera - genetics; Male; MANDUCA; Methods. Procedures. Technologies; Molecular and cellular biology; Molecular cloning; Molecular genetics; Molecular Sequence Data; Moths - genetics; Phylogeny; PROTEASAS; PROTEASE; Protease Inhibitors - genetics; PROTEASES; Proteins - genetics; RNA - genetics; RNA - isolation & purification; Sequence Homology, Nucleic Acid; Serine Proteinase Inhibitors; Sphingidae; Molecular hybridization; Secretion; Insecta; Proteinase; Hemolymph; Enzyme inhibitor; Primary structure; Gene expression; Serpin; Messenger RNA; Complementary DNA; Arthropoda; Elastase; Active center; Fat body; Inhibition; Invertebrata; Aminoacid sequence
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)85038-X

A cDNA clone isolated from a fat body cDNA library from an insect, Manduca sexta, has been sequenced and shown to code for a member of the serpin family of proteinase inhibitors. The cDNA has an open reading frame which codes for a 392-residue polypeptide of Mr = 43,500 with a hydrophobic NH2-terminal sequence which appears to be a signal peptide. An alignment of this amino acid sequence with 11 members of the serpin superfamily reveals that the insect protein is 25–30% identical with most members of the super-family. The alignment was used to construct an evolutionary tree of the serpin sequences analyzed, which indicates that the progenitor of the M. sexta serpin and the human serpins most closely related to it diverged from other serpin genes prior to the divergence of the vertebrates and invertebrates. The M. sexta serpin is predicted to inhibit elastase due to the presence of alanine at the P1 position of its reactive center and is classified as an alaserpin. A glycoprotein of Mr = 47,000 isolated from hemolymph of M. sexta larvae has an NH2-terminal sequence identical to that deduced from the alaserpin cDNA clone and inhibits porcine pancreatic elastase and bovine chymotrypsin.