title: A cysteine-rich protein in the Theromyzon (Annelida: Hirudinea) cocoon membrane.
abstract: The aquatic leech, Theromyzon rude, secretes a flexible, proteinaceous cocoon that is resistant to a broad range of denaturing conditions (e.g. heat, denaturing chemicals). We have partially solubilized the Theromyzon cocoon membrane in 10% acetic acid and identified two major protein fragments. Microsequencing of both Theromyzon cocoon protein (Tcp) fragments generated an identical stretch of the amino-terminal sequence that was used to clone the corresponding gene. The predicted linear amino acid sequence of the resulting cDNA contained an unusually high cysteine content (17.8%). Sequence analysis identified six internal repeats, each comprising 12 ordered Cys residues in a approximately 62 amino acid repeating unit. Sequence comparisons identified homology with undescribed, Cys-rich repeats across animal phyla (i.e. Arthropod, Nematoda).
authors.affiliation: Biology Department, 315 Penn Street, Rutgers, The State University of New Jersey, Camden, NJ 08102, USA.
authors.forename: Tarin A
authors.initials: TA
authors.lastname: Mason
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: McIlroy
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Shain
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001482:Base Composition; D003545:Cysteine; D018076:DNA, Complementary; D007865:Leeches / Q000737:chemistry*; D008018:Life Cycle Stages; D008969:Molecular Sequence Data; D010802:Phylogeny; D011506:Proteins / Q000737:chemistry* / Q000235:genetics*; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein
chemical_list: D018076:DNA, Complementary; D011506:Proteins; D003545:Cysteine