A partially buried site in homologous HPr proteins is not optimized for stability.
A partially buried site in homologous HPr proteins is not optimized for stability.
复制标题
同源 HPr 蛋白中的部分埋藏位点未针对稳定性进行优化。
DOI：
10.1016/s0022-2836(02)00630-7
复制
发表时间：
2002
影响因子：
5.6
通讯作者：
Scholtz,JMartin
中科院分区：
文献类型：
--
作者：
Nicholson,EricM;Peterson,RonaldW;Scholtz,JMartin
描述了在来自大肠杆菌和枯草芽孢杆菌的两个同源HPR蛋白中，部分埋藏位点上的残基被特定位点替换的能量后果。我们先前确定，在E.ColiHPR中第49位用Glu取代部分埋藏的Lys残基大大提高了蛋白质的构象稳定性，因为后者的侧链可以作为氢键受体。在这里，我们将这一分析扩展到其他具有不同化学性质和形成氢键能力的侧链，以比较该位置在两个不同同源HPR蛋白背景下的性质。我们发现，含有极性残基的变体可以与蛋白质中的附近位点形成三级氢键，比疏水残基或被掩埋的极性残基更稳定，但不能形成新的氢键。此外，每个HPR变体中含有野生型残基的蛋白质并不是所研究的蛋白质中最稳定的。这些结果提出了一种设计变体的一般策略，在这种策略中，蛋白质的整体稳定性可以以特定的方式进行调节。
The energetic consequences of site-specific replacement of a residue at a partially buried site in the two homologous HPr proteins from Escherichia coli and Bacillus subtilis is described. We determined previously that the replacement of a partially buried Lys residue with Glu at position 49 in E.coli HPr increased the conformational stability of the protein substantially because the side-chain of the latter residue could act as a hydrogen-bond acceptor. Here, we extend this analysis to other side-chains with different chemical properties and abilities to form hydrogen bonds to compare the properties of this position in the backgrounds of two different homologous HPr proteins. We find that the variants with polar residues that can form a tertiary hydrogen bond with a nearby site in the protein are more stable than either hydrophobic residues or polar residues that become buried yet are incapable of forming a new hydrogen bond. Furthermore, the protein with the wild-type residue in each HPr variant is not among the most stable of the proteins studied. These results suggest a general strategy for designing variants in which the overall stability of a protein can be modulated in a defined fashion.