Amino acid sequence of the regulatory subunit of bovine type I cAMP-dependent protein kinase

Abstract

The complete amino acid sequence of the regulatory subunit of type I cAMP-dependent protein kinase from bovine skeletal muscle is presented. The S-carboxymethylated protein was cleaved with CNBr to provide a complete set of nonoverlapping fragments. These fragments were overlapped and aligned by using peptides generated by proteolytic cleavage. The protein contains 379 amino acid residues corresponding to a MW of 42,804. As in the type II regulatory subunit of cAMP-dependent protein kinase, a pattern of internal gene duplication is observed, which is consistent with 2 cAMP-binding domains. The 2 types of regulatory subunit from type I and type II kinase display similarities in domain substructure and in amino acid sequence, which provide a molecular basis for new insight into their regulatory roles. Detailed analyses of the homology of the regulatory subunits of type I and type II cAMP-dependent protein kinase and of similar relationships to cGMP-dependent protein kinase and Escherchia coli catabolite gene activator protein are presented in accompanying reports from this laboratory.