Lasagna M, Gratton E, Jameson D M, Brunet J E
Instituto de Química, Universidad Católica de Valparaiso, Casilla 4059, Valparaiso, Chile.
Biophys J. 1999 Jan;76(1 Pt 1):443-50. doi: 10.1016/S0006-3495(99)77211-5.
The unfolding and refolding of apohorseradish peroxidase, as a function of guanidinium chloride concentration, were monitored by the intrinsic fluorescence intensity, polarization, and lifetime of the single tryptophan residue. The unfolding was reversible and characterized by at least three distinct stages-the intensity and lifetime data, for example, were both characterized by an initial increase followed by a decrease and then a plateau region. The lifetime data, in the absence and presence of guanidinium chloride, were heterogeneous and fit best to a model consisting of a major Gaussian distribution component and a minor, short discrete component. The observed increase in intensity in the initial stage of the unfolding process is attributed to the conversion of this short component into the longer, distributed component as the guanidinium chloride concentration increases. Our results clarify and amplify previous studies on the unfolding of apohorseradish peroxidase by guanidinium chloride.
通过单一色氨酸残基的固有荧光强度、偏振和寿命，监测了脱辅基辣根过氧化物酶随氯化胍浓度变化的去折叠和再折叠过程。去折叠是可逆的，至少有三个不同阶段——例如，强度和寿命数据的特征都是先增加，然后减少，接着是一个平稳区域。在有和没有氯化胍的情况下，寿命数据都是异质的，最适合由一个主要的高斯分布成分和一个次要的短离散成分组成的模型。在去折叠过程的初始阶段观察到的强度增加，归因于随着氯化胍浓度的增加，这个短成分转化为更长的、分布的成分。我们的结果阐明并扩展了先前关于氯化胍诱导脱辅基辣根过氧化物酶去折叠的研究。
