A model for the calmodulin-peptide complex based on the troponin C crystal packing and its similarity to the NMR structure of the calmodulin-myosin light chain kinase peptide complex.
In the crystal structure of troponin C, the holo C-domain is bound in a head-to-tail fashion to the A-helix of the apo N-domain of a symmetry-related molecule. Using this interaction, we have proposed a model for the calmodulin-peptide complex. We find that the interaction of the C-domain with the A-helix is similar to that observed in the NMR structure of the calmodulin-myosin light chain kinase (MLCK) peptide complex. This similarity in binding has enabled us to make a precise sequence alignment of the target peptides in the calmodulin-binding cleft and to rationalize the amino acid sequence-dependent binding strengths of various peptides. Our model differs from that proposed by Strynadka and James (Proteins Struct. Funct. Genet. 7, 234-248, 1990) in that the peptides are rotated by 100 degrees in the calmodulin binding cleft.
Department of Chemistry, Ohio State University, Columbus 43210.
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Sekharudu
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Sundaralingam
D000595:Amino Acid Sequence; D000818:Animals; D002147:Calmodulin / Q000737:chemistry*; D002645:Chickens; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009219:Myosin-Light-Chain Kinase / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D014336:Troponin / Q000737:chemistry; D019209:Troponin C
D002147:Calmodulin; D046911:Macromolecular Substances; D010455:Peptides; D014336:Troponin; D019209:Troponin C; D009219:Myosin-Light-Chain Kinase