Target enzyme recognition by calmodulin: 2.4 A structure of a calmodulin-peptide complex.Meador, W.E., Means, A.R., Quiocho, F.A.
(1992) Science 257: 1251-1255
- PubMed: 1519061
- DOI: https://doi.org/10.1126/science.1519061
- Primary Citation of Related Structures:
- PubMed 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.
Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030.