Amino-acid sequence of the short subfragment-2 in adult chicken cardiac muscle myosin.

Abstract

The amino-acid sequence of the short subfragment-2 in the amino-terminal portion of subfragment-2 derived from adult chicken ventricular muscle myosin was completely determined by direct protein analysis. Peptides fragmented by cyanogen bromide, lysyl endopeptidase and arginyl endopeptidase of S-carboxymethylated S-2 and peptides of large CNBr peptides cleaved by dilute formic acid were separated and sequenced. This short S-2 composed of 259 amino-acid residues was found highly conserved and contained hydrophobic and charged residue repeat units. Comparing this sequence with the partial nucleotide sequence of cDNA corresponding to short S-2 (Stewart A.F.R., et al. (1991) J. Mol. Evol. 33, 357-366), a 64 amino-acid residues extension towards the NH2 terminus and 9 residues differences were observed. Furthermore, this sequence is compared with those of rat, rabbit and human ventricular myosins, and 86.1%, 86.5%, 86.5% sequence identities are observed, respectively.