The amino-terminal sequences of four major carp γ-crystallin polypeptides and their homology with frog and calf γ-crystallins

AbstractFour major γ-crystallin subfractions have been isolated from the carp (Cyprinus carpio) and their N-terminal sequences determined by Edman protein sequencing. Extensive homologies indicative of close relatedness in their primary structure were found in these four γ-crystallin polypeptides. Comparison of the carp N-terminal sequences with those of mammalian and amphibian γ-crystallins also showed a high degree of homology present in their N-terminal segments despite the dissimilarity of amino acid compositions of fish γ-crystallins to those of higher classes of vertebrates. The distinct yet closely-related partial sequences of carp γ-crystallins could account for the profound microheterogeneity detected in the characterization of carp crystallins, suggesting the presence of a multigene family for γ-crystallin in the lowest class of vertebrates, i.e. the fish