传统的统计调查主要集中在蛋白质腔的简单一维特征的比较,比如数字,表面积,和音量。这些研究未能辨别有助于蛋白质热稳定性的嗜热和嗜温蛋白质之间的空腔性质的关键区别。在这项研究中,空腔性质的意义,即,灵活性和位置,通过比较同源嗜热和嗜温蛋白之间的结构差异来研究蛋白质的热稳定性。蛋白质结构的三个维度分为三个区域(核心,边界,和表面),并使用该结构指数对空腔性能进行了比较分析。统计分析表明,空腔的柔韧性与蛋白质的热稳定性密切相关。嗜热蛋白的核心腔比嗜温蛋白的核心腔柔性低(平均B因子值,-0.6484和-0.5111),这对蛋白质热稳定性的危害可能较小。嗜热蛋白在边界和表面区域表现出更少的空腔。值得注意的是,嗜温蛋白中的空腔,在所有地区,比嗜热蛋白表现出更大的灵活性(>95%的概率)。嗜温蛋白的边界和表面区域中空腔的灵活性增加,与嗜热蛋白相反,可能会损害稳定性。最近涉及嗜温木聚糖酶和蛋白酶的蛋白质工程研究显示,结果与本研究的结果一致。这表明操纵表面区域的柔性空腔可以增强热稳定性。因此,我们的发现表明,在表面或边界区域设计柔性空腔的合理或计算方法可以作为增强嗜温蛋白热稳定性的有效策略。
Conventional statistical investigations have primarily focused on the comparison of the simple one-dimensional characteristics of protein cavities, such as number, surface area, and volume. These studies have failed to discern the crucial distinctions in
cavity properties between thermophilic and mesophilic proteins that contribute to protein thermostability. In this study, the significance of
cavity properties, i.e., flexibility and location, in protein thermostability was investigated by comparing structural differences between homologous thermophilic and mesophilic proteins. Three dimensions of protein structure were categorized into three regions (core, boundary, and surface) and a comparative analysis of
cavity properties using this structural index was conducted. The statistical analysis revealed that
cavity flexibility is closely related to protein thermostability. The core cavities of thermophilic proteins were less flexible than those of mesophilic proteins (averaged B\' factor values, -0.6484 and -0.5111), which might be less deleterious to protein thermostability. Thermophilic proteins exhibited fewer cavities in the boundary and surface regions. Notably, cavities in mesophilic proteins, across all regions, exhibited greater flexibility than those in thermophilic proteins (>95% probability). The increased flexibility of cavities in the boundary and surface regions of mesophilic proteins, as opposed to thermophilic proteins, may compromise stability. Recent protein engineering investigations involving mesophilic xylanase and protease showed results consistent with the findings of this study, suggesting that the manipulation of flexible cavities in the surface region can enhance thermostability. Consequently, our findings suggest that a rational or computational approach to the design of flexible cavities in surface or boundary regions could serve as an effective strategy to enhance the thermostability of mesophilic proteins.