Guevara I, Zak Z
Jan Zurzycki Institute of Molecular Biology, Jagiellonian University, Kraków, Poland.
J Protein Chem. 1993 Apr;12(2):179-85. doi: 10.1007/BF01026039.
Fluorescence quenching of tryptophan residues in egg-white riboflavin-binding protein by two typical quenchers (charged iodide and uncharged acrylamide) reveals acid-induced changes of protein conformation. At neutral pH, acrylamide flow in macromolecule, (i.e., the quenching effect) is decisive; tryptophan residue accessibility for iodide is small. At low pH, some tryptophan residues are exposed to the protein surface and become more accessible to iodide. In contrast, acrylamide is less able to permeate this conformational state of RBP. Fluorescence of tryptophan residues in riboflavin-RBP complex and chemically N-bromosucinimide-modified RBP was quenched by iodide and acrylamide.
两种典型淬灭剂（带电荷的碘化物和不带电荷的丙烯酰胺）对蛋清核黄素结合蛋白中色氨酸残基的荧光淬灭揭示了酸诱导的蛋白质构象变化。在中性pH值下，丙烯酰胺在大分子中的流动（即淬灭效应）起决定性作用；碘化物对色氨酸残基的可及性较小。在低pH值下，一些色氨酸残基暴露于蛋白质表面，对碘化物的可及性增加。相比之下，丙烯酰胺较难渗透到核黄素结合蛋白的这种构象状态中。核黄素-核黄素结合蛋白复合物和化学N-溴代琥珀酰亚胺修饰的核黄素结合蛋白中色氨酸残基的荧光被碘化物和丙烯酰胺淬灭。
