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Isolation of a new class of cysteine–glycine–proline‐rich beta‐proteins (beta‐keratins) and their expression in snake epidermis
Author(s) -
Dalla Valle Luisa,
Nardi Alessia,
Alibardi Lorenzo
Publication year - 2010
Publication title -
journal of anatomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 118
eISSN - 1469-7580
pISSN - 0021-8782
DOI - 10.1111/j.1469-7580.2009.01192.x
Subject(s) - keratin , biology , epidermis (zoology) , beta (programming language) , cysteine , biochemistry , amino acid , intermediate filament , keratin 6a , glycine , microbiology and biotechnology , peptide sequence , genetics , gene , cytoskeleton , cell , anatomy , enzyme , computer science , programming language
Scales of snakes contain hard proteins (beta‐keratins), now referred to as keratin‐associated beta‐proteins. In the present study we report the isolation, sequencing, and expression of a new group of these proteins from snake epidermis, designated cysteine–glycine–proline‐rich proteins. One deduced protein from expressed mRNAs contains 128 amino acids (12.5 kDa) with a theoretical pI at 7.95, containing 10.2% cysteine and 15.6% glycine. The sequences of two more snake cysteine–proline‐rich proteins have been identified from genomic DNA. In situ hybridization shows that the messengers for these proteins are present in the suprabasal and early differentiating beta‐cells of the renewing scale epidermis. The present study shows that snake scales, as previously seen in scales of lizards, contain cysteine‐rich beta‐proteins in addition to glycine‐rich beta‐proteins. These keratin‐associated beta‐proteins mix with intermediate filament keratins (alpha‐keratins) to produce the resistant corneous layer of snake scales. The specific proportion of these two subfamilies of proteins in different scales can determine various degrees of hardness in scales.