cDNA cloning and complete primary structure of skeletal muscle phosphorylase kinase (alpha subunit).

We have isolated and sequenced a cDNA encoding the alpha subunit of phosphorylase kinase from rabbit fast-twitch skeletal muscle. The cDNA molecule consists of 388 nucleotides of 5'-nontranslated sequence, the complete coding sequence of 3711 nucleotides, and 342 nucleotides of 3'-nontranslated sequence followed by a poly(dA) tract. It encodes a polypeptide of 1237 amino acids and a deduced molecular mass of 138,422 Da. Nearly half of the deduced amino acid sequence is confirmed by peptide sequencing. Seven positions of endogenously phosphorylated serine residues and autophosphorylation sites, identified by peptide sequencing, could be assigned. They cluster in a segment of only 60 amino acids. RNA blot hybridization analysis demonstrates a predominant RNA species of approximately equal to 4500 nucleotides and a less abundant RNA of 8700 nucleotides.