title: beta-Keratins in crocodiles reveal amino acid homology with avian keratins.
abstract: The DNA sequences encoding beta-keratin have been obtained from Marsh Mugger (Crocodylus palustris) and Orinoco Crocodiles (Crocodylus intermedius). Through the deduced amino acid sequence, these proteins are rich in glycine, proline and serine. The central region of the proteins are composed of two beta-folded regions and show a high degree of identity with beta-keratins of aves and squamates. This central part is thought to be the site of polymerization to build the framework of beta-keratin filaments. It is believed that the beta-keratins in reptiles and birds share a common ancestry. Near the C-terminal, these beta-keratins contain a peptide rich in glycine-X and glycine-X-X, and the distinctive feature of the region is some 12-amino acid repeats, which are similar to the 13-amino acid repeats in chick scale keratin but absent from avian feather keratin. From our phylogenetic analysis, the beta-keratins in crocodile have a closer relationship with avian keratins than the other keratins in reptiles.
authors.affiliation: College of Life Sciences, and Key Laboratory for Conservation and Exploitation of Biological Resource in Anhui Province, Anhui Normal University, Wuhu, China.
authors.forename: Changjiang
authors.initials: C
authors.lastname: Ye
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Wu
authors.forename: Peng
authors.initials: P
authors.lastname: Yan
authors.forename: George
authors.initials: G
authors.lastname: Amato
mesh_terms: D000489:Alligators and Crocodiles / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001717:Birds / Q000235:genetics*; D016000:Cluster Analysis; D017931:DNA Primers / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D011487:Protein Conformation; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013045:Species Specificity; D053800:beta-Keratins / Q000235:genetics*
chemical_list: D017931:DNA Primers; D053800:beta-Keratins