title: Target enzyme recognition by calmodulin: 2.4 A structure of a calmodulin-peptide complex.
abstract: The crystal structure of calcium-bound calmodulin (Ca(2+)-CaM) bound to a peptide analog of the CaM-binding region of chicken smooth muscle myosin light chain kinase has been determined and refined to a resolution of 2.4 angstroms (A). The structure is compact and has the shape of an ellipsoid (axial ratio approximately 2:1). The bound CaM forms a tunnel diagonal to its long axis that engulfs the helical peptide, with the hydrophobic regions of CaM melded into a single area that closely covers the hydrophobic side of the peptide. There is a remarkably high pseudo-twofold symmetry between the closely associated domains. The central helix of the native CaM is unwound and expanded into a bend between residues 73 and 77. About 185 contacts (less than 4 A) are formed between CaM and the peptide, with van der Waals contacts comprising approximately 80% of this total.
authors.affiliation: Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030.
authors.forename: W E
authors.initials: WE
authors.lastname: Meador
authors.forename: A R
authors.initials: AR
authors.lastname: Means
authors.forename: F A
authors.initials: FA
authors.lastname: Quiocho
mesh_terms: D000595:Amino Acid Sequence; D002147:Calmodulin / Q000737:chemistry*; D003461:Crystallography; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism*; D011487:Protein Conformation
chemical_list: D002147:Calmodulin; D009219:Myosin-Light-Chain Kinase