SURFACE ELECTROSTATIC INTERACTIONS CONTRIBUTE LITTLE TO STABILITY OF BARNASE
SURFACE ELECTROSTATIC INTERACTIONS CONTRIBUTE LITTLE TO STABILITY OF BARNASE
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DOI：
10.1016/0022-2836(91)90117-o
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发表时间：
1991-08-05
影响因子：
5.6
通讯作者：
FERSHT, AR
中科院分区：
文献类型：
--
作者：
SALI, D;BYCROFT, M;FERSHT, AR
静电相互作用被认为在稳定蛋白质的天然结构方面发挥着重要作用。我们量化了Barnase表面两个相反电荷侧链之间相互作用对稳定性的贡献。利用定点突变技术，将谷氨酸28和赖氨酸32引入到Barnase中第二个α-螺旋的溶剂可及侧。这两个残基被螺旋一圈分开，因此处于它们相反的电荷相互作用的理想位置。双突变循环分析表明，Glu28和Lys32之间的相互作用仅对蛋白质的稳定性贡献约0.2kcal/mol。到目前为止，所研究的藤壶酶中暴露的带电侧链之间的所有其他相互作用对稳定性也没有什么贡献。我们通过它们在蛋白质表面的位置来解释这种低价值，而不是在蛋白质的内部。
Electrostatic interactions are believed to play an important role in stabilizing the native structure of proteins. We have quantified the contribution to stability of an interaction between two oppositely charged side-chains on the surface of barnase. Using site-directed mutagenesis, glutamate 28 and lysine 32 were introduced onto the solvent-accessible side of the second α-helix in barnase. These two residues are separated by one turn of the helix, and so are ideally situated for their opposite charges to interact. Double mutant cycle analysis reveals that the interaction between Glu28 and Lys32 contributes only approximately 0.2 kcal/mol to stability of the protein. All other interations between exposed charged side-chains in barnase examined so far also contribute little to stability. We explain this low value by their location on the surface, rather than in the interior, of the protein.