The functional nature of calcium binding units in calmodulin, troponin C and parvalbumin.
Examination of the interaction of major tranquilizers with calmodulin results in the generalization that the functional nature of calcium binding helix-loop-helix regions found in several calcium binding proteins including calmodulin, troponin C and parvalbumin is dependent upon the topography of the hydrophobic and hydrophilic regions on the amphiphilic N-terminal alpha-helix of the helix-loop-helix conformation formed by the binding of the calcium cation to these proteins. The relation of the topography of this amphiphilic alpha-helix to drug binding is delineated at the molecular level and the results obtained are used to describe the interaction of beta-endorphin, dynorphin, alpha-MSH and other peptides with calmodulin. The utility of this hypothesis is further demonstrated by the description of a possible interaction between troponin C, troponin I and troponin T of the troponin complex in skeletal muscle.
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D000595:Amino Acid Sequence; D000818:Animals; D014150:Antipsychotic Agents / Q000378:metabolism; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism*; D002417:Cattle; D004723:Endorphins / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D008958:Models, Molecular; D009124:Muscle Proteins / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism*; D011487:Protein Conformation; D011817:Rabbits; D014336:Troponin / Q000378:metabolism*; D019209:Troponin C; D019210:Troponin I; D020107:Troponin T
D014150:Antipsychotic Agents; D002147:Calmodulin; D004723:Endorphins; D009124:Muscle Proteins; D010320:Parvalbumins; D014336:Troponin; D019209:Troponin C; D019210:Troponin I; D020107:Troponin T; D002118:Calcium