Conformational Changes Induced by Binding of Divalent Cations to Calregulin

摘要: Scatchard analysis of equilibrium dialysis studies have revealed that in the presence 3.0 mM MgCl2 and 150 KCl, calregulin has a single binding site for Ca2+ with an apparent dissociation constant (apparent Kd) 0.05 microM 14 sites Zn2+ Kd(Zn2+) 310 microM. to induces 5% increase intensity intrinsic fluorescence 2-3-nm blue shift emission maximum. causes dose-dependent about 250% its red maximum 11 nm. Half-maximal wavelength occurs at 0.4 mol Zn2+/mol calregulin, 100% is complete 2 calregulin. In hydrophobic fluorescent probe 8-anilino-1-napthalenesulfonate (ANS) was enhanced 300-400% from 500 480 Zn2+-induced ANS occurred 1.2 this 6 Of 12 cations tested, only produced changes fluorescence, none these metal ions could inhibit Furthermore, or mimic These results suggest contains distinct specific ligand-binding Zn2+. While movement tryptophan away solvent, into solvent exposure domain considerable character.