Cox J A, Winge D R, Stein E A
Biochimie. 1979;61(5-6):601-5. doi: 10.1016/s0300-9084(79)80157-1.
The conformation of perch parvalbumin in the Ca-, Mg- and metal-free state was studied by intrinsic fluorescence, trypsin susceptibility, thiol titration and circular dichroism. The data reveal that Ca-parvalbumin has a more compact structure than the metal-free protein, with a high alpha-helical content and a buried thiol. No difference in conformation could be detected between Mg- and Ca-parvalvumin, indicating that the Ca-Mg exchange that may take place during muscular activity is accompanied by little or no structural changes. Furthermore, recently published kinetic parameters can now be interpreted as meaning that, during the contraction-relaxation cycle, parvalbumin often stays in the Mg-form instead of switching to the Ca-form which is predominant in vitro.
通过内源荧光、胰蛋白酶敏感性、巯基滴定和圆二色性研究了鲈鱼小清蛋白在含钙、含镁和无金属状态下的构象。数据显示，钙结合小清蛋白比无金属蛋白具有更紧密的结构，具有高α-螺旋含量和一个埋藏的巯基。未检测到镁结合小清蛋白和钙结合小清蛋白在构象上的差异，这表明在肌肉活动期间可能发生的钙-镁交换几乎没有或没有伴随结构变化。此外，最近公布的动力学参数现在可以解释为，在收缩-舒张周期中，小清蛋白经常保持镁结合形式，而不是转换为在体外占主导的钙结合形式。
