Calcium-dependent interaction of S100b, troponin C, and calmodulin with an immobilized phenothiazine.
We have purified the brain-specific protein S100b by affinity-based adsorption chromatography on phenothiazine-Sepharose conjugates and studied the interaction of this and other calcium-modulated proteins with the immobilized antipsychotic drug. Bovine brain calmodulin, rabbit skeletal muscle troponin C, and bovine brain S100b bind to phenothiazine-Sepharose in a calcium-dependent manner. These three proteins competitively inhibit the calcium-dependent binding of 125I-labeled chicken gizzard calmodulin to the immobilized drug. However, carp parvalbumin and chicken intestinal vitamin D-dependent calcium binding protein do not inhibit the phenothiazine--calmodulin interaction. These results suggest that the known amino acid sequence homology among calmodulin, troponin C, and S100b may be reflected in a similar functional domain present in these proteins but absent in parvalbumin and vitamin D-dependent protein.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism*; D002417:Cattle; D002746:Chlorpromazine / Q000031:analogs & derivatives*; D002846:Chromatography, Affinity; D007700:Kinetics; D009124:Muscle Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000302:isolation & purification / Q000378:metabolism*; D011817:Rabbits; D009418:S100 Proteins / Q000302:isolation & purification / Q000378:metabolism*; D014336:Troponin / Q000378:metabolism*; D019209:Troponin C
D002135:Calcium-Binding Proteins; D002147:Calmodulin; D009124:Muscle Proteins; D009419:Nerve Tissue Proteins; D009418:S100 Proteins; D014336:Troponin; D019209:Troponin C; C022892:didemethylchlorpromazine; D002118:Calcium; D002746:Chlorpromazine