Document Detail

Crystal structure of calmodulin.
MedLine Citation:
PMID:  3806094     Owner:  NLM     Status:  MEDLINE    
The crystal structure of calmodulin has been determined to 3.6 A resolution. At this resolution the polypeptide chain can be traced. Some of the side chains have tentatively been identified. Refinement of the structure with x-ray diffraction data measured to 1.65 A resolution is continuing. As reported by Babu et al. calmodulin is about 65 A long and 30 A in diameter. Homolog domains 1 and 2 are related by a local twofold axis, as in parvalbumin and in troponin C, and form one end of the molecule. Domains 3 and 4 form the other end. The second alpha-helix of domain 2 and a short interdomain region are continuous with the first helix of domain 3, thereby forming a single helix from residues 67-93. The central region, residues 75-84, of this long helix forms a handle connecting the two pairs of homolog domains. Exclusive of the residues, 75-84, in the handle the closet approach of side chains of pair 1, 2 to pair 3, 4 is 12 A. The spatial relationship of pair 1, 2 to pair 3, 4 is similar in calmodulin to the relationship of the corresponding pairs in troponin C. However, in troponin C there are three additional residues in the handle region of the long alpha-helix and the two pairs are about 5.0 A further apart. On the surface of pair 1, 2 in calmodulin there is one extended region with many hydrophobic side chains from both domain 1 and domain 2. This hydrophobic patch is bounded by two distinct clusters of anionic side chains, one from the beginning of the first helix of domain 1 and on the other side of the hydrophobic surface one from the beginning of the first helix of domain 2. Homologously, the hydrophobic patch on the surface of pair 3, 4 is bounded by two clusters of aspartate and glutamate residues. Either or both of these hydrophobic surfaces may be sites to which calmodulin target proteins bind.
R H Kretsinger; S E Rudnick; L J Weissman
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of inorganic biochemistry     Volume:  28     ISSN:  0162-0134     ISO Abbreviation:  J. Inorg. Biochem.     Publication Date:    1986 Oct-Nov
Date Detail:
Created Date:  1987-03-23     Completed Date:  1987-03-23     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7905788     Medline TA:  J Inorg Biochem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  289-302     Citation Subset:  IM; S    
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MeSH Terms
Amino Acid Sequence
Models, Molecular
Protein Conformation
Structure-Activity Relationship
Troponin C
X-Ray Diffraction
Grant Support
Reg. No./Substance:
0/Calmodulin; 0/Troponin; 0/Troponin C

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