Antiparallel alignment of the two protomers of the regulatory subunit dimer of cAMP-dependent protein kinase I

• Published in: The Journal of biological chemistry Vol. 262; no. 31; pp. 14961 - 14966
• Main Authors: Bubis, J, Vedvick, T S, Taylor, S S
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 05.11.1987; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; Macromolecular Substances; Peptide Fragments - analysis; Promoter Regions, Genetic; Protein Kinases - genetics; Transferases; Trypsin; Cysteine; Enzyme; Edman degradation; HPLC chromatography; GMP; Regulatory subunit; Molecular asymmetry; Striated muscle; Orientation; Pig; Aggregation; Vertebrata; Mammalia; Disulfide bond; Protein kinase; Protomer; Dimer; Artiodactyla; Ungulata
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)48122-7

The purified type I regulatory subunit of cAMP-dependent protein kinase is a dimeric protein, and the two protomers of the dimer are linked by two interchain disulfide bonds. The disulfide linkages that join these two polypeptide chains have been identified in order to provide a structural basis for the orientation of the two chains in the asymmetric dimer. Disulfide bonds were found to exist exclusively between Cys-16 and Cys-37, and this assignment, thus, establishes a general antiparallel alignment of the two chains. Two other homologous proteins, the type II regulatory subunit and the cGMP-dependent protein kinase also are dimeric proteins. In all three proteins, a relatively small, nonhomologous, amino-terminal segment of the polypeptide chain is essential for maintaining the dimeric aggregation state.