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A cysteine‐rich protein in the Theromyzon (Annelida: Hirudinea) cocoon membrane
Author(s) -
Mason Tarin A,
McIlroy Patrick J,
Shain Daniel H
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(04)00167-x
Subject(s) - cysteine , chemistry , zoology , biology , microbiology and biotechnology , biochemistry , enzyme
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 ∼62 amino acid repeating unit. Sequence comparisons identified homology with undescribed, Cys‐rich repeats across animal phyla (i.e. Arthropod, Nematoda).