Low Lawrence K, Shin Hang-Cheol, Scheraga Harold A
Baker Laboratory of Chemistry & Chemical Biology, Cornell University, Ithaca, NY 14853-1301, USA.
J Protein Chem. 2002 Jan;21(1):19-27. doi: 10.1023/a:1014174930972.
The effects of the strong stabilizing anion, phosphate, on the oxidative folding of bovine pancreatic ribonuclease A were examined. Phosphate was found to catalyze several steps involved in the oxidative folding process at pH 8.0 and 25 degrees C, resulting in an increase in the rate of pre-equilibration of unstructured species on the folding pathway. In the presence of 400 mM phosphate, the overall increase in the rate of regeneration of native protein was caused primarily by the increased formation and stabilization of tertiary structure in the nativelike intermediates, des-[40-95] and des-[65-72], involved in the rate-determining step. Based on the regeneration of native protein and the stability of Cys--> Ala substituted mutant analogs of the des-species, (C40A, C95A) and (C65A, C72A), it is suggested that the primary role of phosphate is to catalyze the overall regeneration of native protein through nonspecific electrostatic and hydrogen-bonding effects on the protein and solvent.
研究了强稳定阴离子磷酸盐对牛胰核糖核酸酶A氧化折叠的影响。发现在pH 8.0和25℃条件下，磷酸盐催化氧化折叠过程中的几个步骤，导致折叠途径上无结构物种的预平衡速率增加。在400 mM磷酸盐存在下，天然蛋白质再生速率的总体增加主要是由于参与速率决定步骤的类天然中间体des-[40-95]和des-[65-72]中三级结构形成和稳定性的增加。基于天然蛋白质的再生以及des-物种（C40A、C95A）和（C65A、C72A）的半胱氨酸→丙氨酸取代突变体类似物的稳定性，表明磷酸盐的主要作用是通过对蛋白质和溶剂的非特异性静电和氢键作用催化天然蛋白质的整体再生。
