Conformational and hydrophobic properties of rat and bovine S-100 proteins.
The binding of Ca2+ to rat or bovine S-100 proteins, in the absence of ligands, showed a dissociation constant (in 60 mM K+) of 0.5 to 1.0 mM as measured by the effects of Ca2+ on binding of S-100 to phenyl-Sepharose, reactivity of sulfhydryl groups, and difference spectra for PHE, TYR, and TRP residues. Binding of the ligands, "Stainsall" and chlorpromazine lowered the dissociation constant of S-100 for Ca2+ by 2- to 10-fold as measured by the same parameters. The conformational change, in response to Ca2+ binding, probably occurs by exposure to solvent of the hydrophobic region of alpha and beta subunits of S-100 at residue positions 74-93.
Moore
B W
BW
Washington University Medical School, Department of Psychiatry, St. Louis, MO 63110.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002232:Carbocyanines / Q000378:metabolism; D002417:Cattle; D002746:Chlorpromazine / Q000494:pharmacology; D004228:Dithionitrobenzoic Acid / Q000378:metabolism; D007700:Kinetics; D008968:Molecular Conformation; D051381:Rats; D009418:S100 Proteins / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism
D002232:Carbocyanines; D009418:S100 Proteins; D013438:Sulfhydryl Compounds; C012040:stains-all; D004228:Dithionitrobenzoic Acid; D002118:Calcium; D002746:Chlorpromazine