Refolding behavior of a kinetic intermediate observed in the low pH unfolding of ribonuclease A.
Refolding behavior of a kinetic intermediate observed in the low pH unfolding of ribonuclease A.
复制标题
在核糖核酸酶 A 的低 pH 解折叠中观察到的动力学中间体的重折叠行为。
作者：
P. Hagerman;F. Schmid;R. L. Baldwin
以前在核糖核酸酶A的去折叠过程中观察到的一种瞬时中间体(I_3)已经通过使用顺序混合仪器选择性地填充这一物种而被研究。这种方法使得确定该物种的折叠行为和进一步表征其形成的动力学成为可能。(1)I3的形成是最早可检测到的展开变化。(2)当蛋白质内部暴露在溶剂中时，2‘cMP结合位点的丢失是平行发生的。(3)I3在复性过程中不同于以前描述的中间体。(4)蛋白质的整个缩合过程约在30ms(pH 5.8，47℃)内发生，以排除内部的溶剂，以及底物结合部位的形成，这表明天然结构的形成可能比先前假设的更快。
A transient intermediate (I3) observed previously in the unfolding of ribonuclease A has been studied by employing a sequential mixing instrument to populate selectively this species. This approach has made it possible both to determine the refolding behavior of this species and to characterize further the kinetics of its formation. (1) Formation of I3 represents the earliest detectable change in unfolding. (2) The loss of the 2'CMP binding site occurs in parallel with the exposure of the interior of the protein to solvent. (3) I3 is distinct from previously described intermediates in refolding. (4) Overall condensation of the protein to exclude solvent from the interior, as well as the formation of a substrate binding site, takes place in approximately 30 ms (pH 5.8, 47 degrees C), indicating that the formation of native structure can take place faster than had previously been supposed.