title: Structure of a peptide inhibitor bound to the catalytic subunit of cyclic adenosine monophosphate-dependent protein kinase.
abstract: The structure of a 20-amino acid peptide inhibitor bound to the catalytic subunit of cyclic AMP-dependent protein kinase, and its interactions with the enzyme, are described. The x-ray crystal structure of the complex is the basis of the analysis. The peptide inhibitor, derived from a naturally occurring heat-stable protein kinase inhibitor, contains an amphipathic helix that is followed by a turn and an extended conformation. The extended region occupies the cleft between the two lobes of the enzyme and contains a five-residue consensus recognition sequence common to all substrates and peptide inhibitors of the catalytic subunit. The helical portion of the peptide binds to a hydrophobic groove and conveys high affinity binding. Loops from both domains converge at the active site and contribute to a network of conserved residues at the sites of magnesium adenosine triphosphate binding and catalysis. Amino acids associated with peptide recognition, nonconserved, extend over a large surface area.
authors.affiliation: Department of Chemistry, University of California, San Diego, La Jolla 92093-0654.
authors.forename: D R
authors.initials: DR
authors.lastname: Knighton
authors.forename: J H
authors.initials: JH
authors.lastname: Zheng
authors.forename: L F
authors.initials: LF
authors.lastname: Ten Eyck
authors.forename: N H
authors.initials: NH
authors.lastname: Xuong
authors.forename: S S
authors.initials: SS
authors.lastname: Taylor
authors.forename: J M
authors.initials: JM
authors.lastname: Sowadski
mesh_terms: D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D003198:Computer Simulation; D004791:Enzyme Inhibitors / Q000737:chemistry*; D047908:Intracellular Signaling Peptides and Proteins; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011494:Protein Kinases / Q000737:chemistry* / Q000378:metabolism; D014961:X-Ray Diffraction
chemical_list: D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D046911:Macromolecular Substances; C015482:protein kinase modulator; D011494:Protein Kinases