Primary structure of the hinge region in adult chicken cardiac myosin subfragment-2.
The complete amino-acid sequence of the hinge region in the subfragment-2 (S-2) derived from adult chicken cardiac ventricular muscle myosin has been determined by direct protein sequencing. The entire amino-acid sequence of this hinge composed of 143 residues was established by structural analysis of CNBr peptides, lysyl and arginyl endopeptidase peptides of carboxymethylated S-2. By sequence comparison with the corresponding region of the same chicken cardiac myosin which was recently deduced from its cDNA eight amino-acid differences were recognized. Comparing the sequence of this hinge with those of other cardiac myosins such as rat alpha- and beta-myosin heavy chains (MHC), rabbit alpha-MHC and human alpha- and beta-MHCs relatively lower degrees of sequence identities, namely 74.8%, 77.6%, 76.1% 75.5% and 75.5%, are observed. On the other hand, more than 89.5% sequence identities are shown among these mammalian cardiac myosins. These results indicate that avian cardiac MHC has diverged earlier than mammalian cardiac myosin has diverged to alpha- and beta-MHC. Amino-acid substitutions in this hinge region form a cluster on the C-terminal sequence region. On the contrary, in the N-terminal portion, completely conserved segments are observed, suggesting that these regions may contribute to the myosin ATPase activity and muscle contraction.
Watanabe
B
B
School of Allied Medical Sciences, Nagasaki University, Japan.
Tanigawa
M
M
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002645:Chickens; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D008969:Molecular Sequence Data; D009200:Myocardial Contraction; D009206:Myocardium / Q000737:chemistry*; D015879:Myosin Subfragments / Q000737:chemistry*; D051381:Rats; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000378:metabolism
D000596:Amino Acids; D015879:Myosin Subfragments; D012697:Serine Endopeptidases; C060325:arginine endopeptidase; C036813:lysyl endopeptidase