Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA.
Protein Sci. 2010 May;19(5):929-43. doi: 10.1002/pro.370.
The goal of this article is to gain a better understanding of the denatured state ensemble (DSE) of proteins through an experimental and computational study of their denaturation by urea. Proteins unfold to different extents in urea and the most hydrophobic proteins have the most compact DSE and contain almost as much secondary structure as folded proteins. Proteins that unfold to the greatest extent near pH 7 still contain substantial amounts of secondary structure. At low pH, the DSE expands due to charge-charge interactions and when the net charge per residue is high, most of the secondary structure is disrupted. The proteins in the DSE appear to contain substantial amounts of polyproline II conformation at high urea concentrations. In all cases considered, including staph nuclease, the extent of unfolding by urea can be accounted for using the data and approach developed in the laboratory of Wayne Bolen (Auton et al., Proc Natl Acad Sci 2007; 104:15317-15323).
本文的目的是通过对蛋白质在脲中的变性的实验和计算研究，更好地了解变性状态集合（DSE）。在脲中，蛋白质的变性程度不同，最疏水的蛋白质具有最紧凑的 DSE，并且包含与折叠蛋白质几乎相同量的二级结构。在 pH 值为 7 附近变性程度最大的蛋白质仍然含有大量的二级结构。在低 pH 值下，由于电荷-电荷相互作用，DSE 会扩展，并且当每个残基的净电荷较高时，大部分二级结构会被破坏。在高浓度脲中，DSE 中的蛋白质似乎含有大量的聚脯氨酸 II 构象。在所有考虑的情况下，包括枯草杆菌核酸酶，脲的变性程度可以使用 Wayne Bolen 实验室开发的数据和方法来解释（Auton 等人，Proc Natl Acad Sci 2007；104:15317-15323）。
