Target Enzyme Recognition by Calmodulin: 2.4 overset{circ}{mathrm A} Structure of a Calmodulin-Peptide Complex
Abstract
The crystal structure of calcium-bound calmodulin (Ca2+-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 (overset{circ}{mathrm A}). The structure is compact and has the shape of an ellipsoid (axial ratio ~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 (<4 overset{circ}{mathrm A}) are formed between CaM and the peptide, with van der Waals contacts comprising ~80% of this total.
- Publication:
-
Science
- Pub Date:
- August 1992
- DOI:
- 10.1126/science.1519061
- Bibcode:
- 1992Sci...257.1251M