Robinson-Rechavi Marc, Godzik Adam
Joint Center for Structural Genomics, University of California, San Diego, La Jolla, California 92093, USA.
Structure. 2005 Jun;13(6):857-60. doi: 10.1016/j.str.2005.03.011.
Despite numerous studies, understanding the structural basis of protein stability in thermophilic organisms has remained elusive. One of the main reasons is the limited number of thermostable protein structures available for analysis, but also the difficulty in identifying relevant features to compare. Notably, an intuitive feeling of "compactness" of thermostable proteins has eluded quantification. With the unprecedented opportunity to assemble a data set for comparative analyses due to the recent advances in structural genomics, we can now revisit this issue and focus on experimentally determined structures of proteins from the hyperthermophilic bacterium Thermotoga maritima. We find that 73% of T. maritima proteins have higher contact order than their mesophilic homologs. Thus, contact order, a structural feature that was originally introduced to explain differences in folding rates of different protein families, is a significant parameter that can now be correlated with thermostability.
尽管进行了大量研究，但对于嗜热生物中蛋白质稳定性的结构基础仍难以理解。主要原因之一是可用于分析的耐热蛋白质结构数量有限，而且难以识别相关特征进行比较。值得注意的是，耐热蛋白质“紧密性”的直观感受一直难以量化。由于结构基因组学的最新进展，我们有了前所未有的机会组装一个用于比较分析的数据集，现在我们可以重新审视这个问题，并专注于来自超嗜热细菌海栖热袍菌（Thermotoga maritima）的蛋白质的实验确定结构。我们发现，73%的海栖热袍菌蛋白质的接触序高于其嗜温同源物。因此，接触序这一最初用于解释不同蛋白质家族折叠速率差异的结构特征，现在是一个可以与热稳定性相关联的重要参数。
