Bastiras S, Wallace J C
Bresatec Limited, Adelaide, Australia.
Biochemistry. 1992 Sep 29;31(38):9304-9. doi: 10.1021/bi00153a025.
Equilibrium denaturation of recombinant porcine growth hormone (pGH) derived from Escherichia coli using the denaturant guanidine hydrochloride (GuHCl) was followed by ultraviolet absorption spectroscopy, intrinsic fluorescence, far-ultraviolet circular dichroism, and size-exclusion chromatography. The normalized denaturation transition curves for each of the above methods were not coincident; denaturation resulted in an initial disruption of the tertiary structure, whereas secondary structure and degree of compactness were disrupted at higher concentrations of denaturant. Size-exclusion chromatography also detected an associated form of pGH at intermediate GuHCl concentrations. These findings conclusively show that pGH does not follow a simple two-state folding mechanism but are consistent with the framework model of folding. Stable intermediates observed were similar to those seen in other nonhuman growth hormones and are characterized as compact and largely alpha-helical yet lacking nativelike tertiary structure.
利用变性剂盐酸胍（GuHCl）对源自大肠杆菌的重组猪生长激素（pGH）进行平衡变性研究，采用了紫外吸收光谱、内源荧光、远紫外圆二色光谱和尺寸排阻色谱法。上述每种方法的归一化变性转变曲线并不重合；变性导致三级结构首先被破坏，而二级结构和紧密程度在更高浓度的变性剂作用下才被破坏。尺寸排阻色谱法还在中等GuHCl浓度下检测到了pGH的一种缔合形式。这些发现确凿地表明，pGH并不遵循简单的两态折叠机制，而是与折叠的框架模型一致。观察到的稳定中间体与其他非人生长激素中的类似，其特征是结构紧密且主要为α螺旋结构，但缺乏类似天然的三级结构。
