Structural distribution of stability in a thermophilic enzyme
Structural distribution of stability in a thermophilic enzyme
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DOI：
10.1073/pnas.96.24.13674
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发表时间：
1999-11-23
影响因子：
11.1
通讯作者：
Marqusee, S
中科院分区：
文献类型：
--
作者：
Hollien, J;Marqusee, S
不含半胱氨酸的嗜热嗜热菌核糖核酸酶H的单个残基的稳定性参数是通过自然态氢交换确定的，从而提供了嗜热性和中温性同系物之间唯一的区域热力学比较。嗜热蛋白的稳定性总体分布与其中温同系物相似，几乎AN残基的稳定性成比例增加。因此，在全局稳定性相同的条件下，这两种蛋白质的特定残基稳定性非常相似。这些结果表明，嗜热杆菌核糖核酸酶H是以非定域的方式稳定的，在整个结构中保持了稳定相互作用的微调平衡。因此，虽然蛋白质的稳定性可以通过单一氨基酸的替代来改变，但进化到最佳功能可能需要更微妙和离域的机制。
Stability parameters for individual residues in Thermus thermophilus cysteine-free RNase H were determined by native state hydrogen exchange, thus providing a unique comparison of regional thermodynamics between thermophilic and mesophilic homologues. The general distribution of stability in the thermophilic protein is similar to that of its mesophilic homologue, with a proportional increase in stability for almost an residues. As a consequence, the residue-specific stabilities of the two proteins are remarkably similar under conditions where their global stabilities are the same. These results indicate that T. thermophilus RNase H is stabilized in a delocalized fashion, preserving a finely tuned balance of stabilizing interactions throughout the structure. Therefore, although protein stability can be altered by single amino acid substitution, evolution for optimal function may require more subtle and delocalized mechanisms.