Rescuing a destabilized protein fold through backbone cyclization
Rescuing a destabilized protein fold through backbone cyclization
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DOI：
10.1006/jmbi.2001.4631
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发表时间：
2001-05-18
影响因子：
5.6
通讯作者：
Muir, TW
中科院分区：
文献类型：
--
作者：
Camarero, JA;Fushman, D;Muir, TW
我们描述了各种圆形和线性形式的相似的60残基n端Src同源3 （SH3）结构域从小鼠c-Crk适配蛋白的物理化学性质。结构、动力学、热力学、动力学和生化研究表明，主链环化并不妨碍任何环状蛋白采用自然折叠结构。蛋白质的折叠速率和展开速率在圆化过程中都有轻微的增加。环状化并没有导致全长蛋白的显著热力学稳定性，这表明不稳定的焓效应（如应变）抵消了预期的有利熵对整体稳定性的贡献。相反，我们发现环状化导致缺乏关键谷氨酸残基的SH3结构域的截断版本显着稳定。挽救不稳定突变体的能力表明，环状化可能是蛋白质工程程序中一个有用的工具，旨在产生最小化的蛋白质。(C) 2001学术出版社。
We describe the physicochemical characterization of various circular and linear forms of the similar to 60 residue N-terminal Src homology 3 (SH3) domain from the murine c-Crk adapter protein. Structural, dynamic, thermodynamic, kinetic and biochemical studies reveal that backbone circularization does not prevent the adoption of the natural folded structure in any of the circular proteins. Both the folding and unfolding rate of the protein increased slightly upon circularization. Circularization did not lead to a significant thermodynamic stabilization of the full-length protein, suggesting that destabilizing enthalpic effects (e.g. strain) negate the expected favorable entropic contribution to overall stability. In contrast, we find circularization results in a dramatic stabilization of a truncated version of the SH3 domain lacking a key glutamate residue. The ability to rescue the destabilized mutant indicates that circularization may be a useful tool in protein engineering programs geared towards generating minimized proteins. (C) 2001 Academic Press.