The α and β Subunits of Phosphorylase Kinase are Homologous: cDNA Cloning and Primary Structure of the β Subunit

• Published in: Proceedings of the National Academy of Sciences - PNAS 1988-12, Vol.85 (24), p.9381-9385
• Main Authors: Kilimann, Manfred W., Zander, Norbert F., Kuhn, Carl C., Crabb, John W., Meyer, Helmut E., Ludwig M. G. Heilmeyer
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Analytical, structural and metabolic biochemistry; Animals; Base Sequence; Binding Sites; Biochemistry; Biological and medical sciences; Calmodulin - metabolism; Cloning, Molecular; Complementary DNA; DNA - analysis; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; Ligands; Macromolecular Substances; Methionine; Molecular Sequence Data; Molecular Weight; Molecules; Phosphates; Phosphorylase Kinase - analysis; Phosphorylase Kinase - genetics; Phosphorylation; Protein Processing, Post-Translational; Proteins; Rabbits; Sequencing; Transferases
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.85.24.9381

We have cloned cDNA molecules encoding the β subunit of phosphorylase kinase (ATP:phosphorylase-b phosphotransferase; EC 2.7.1.38) from rabbit fast-twitch skeletal muscle and have determined the complete primary structure of the polypeptide by a combination of peptide and DNA sequencing. In the mature β subunit, the initial methionine is replaced by an acetyl group. The subunit is composed of 1092 amino acids and has a calculated molecular mass of 125,205 Da. Alignment of its sequence with the α subunit of phosphorylase kinase reveals extensive regions of homology, but each molecule also possesses unique sequences. Two of the three phosphorylation sites known for the β subunit and all seven phosphorylation sites known for the α subunit are located in these unique domains.