Salt‐bridges play a unique role in the structural and functional stability of proteins, especially under harsh environments. How these salt‐bridges contribute to the overall thermodynamic stability of protein structure and function across different domains of life is elusive still date. To address the issue, statistical analyses on the energies of salt‐bridges, involved in proteins' structure and function, are performed across three domains of life, that is, archaea, eubacteria, and eukarya. Results show that although the majority of salt‐bridges are stable and conserved, yet the stability of archaeal proteins (∆∆G _net = −5.06 ± 3.8) is much more than that of eubacteria (∆∆G _net = −3.7 ± 2.9) and eukarya (∆∆G _net = −3.54 ± 3.1). Unlike earlier study with archaea, in eukarya and eubacteria, not all buried salt‐bridge in our dataset are stable. Buried salt‐bridges play surprising role in protein stability, whose variations are clearly observed among these domains. Greater desolvation penalty of buried salt‐bridges is compensated by stable network of salt‐bridges apart from equal contribution of bridge and background energy terms. On the basis proteins' secondary structure, topology, and evolution, our observation shows that salt‐bridges when present closer to each other in sequence tend to form a greater number. Overall, our comparative study provides insight into the role of specific electrostatic interactions in proteins from different domains of life, which we hope, would be useful for protein engineering and bioinformatics study.

中文翻译：

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离子对能量，生活中三个域之间分布的比较研究：古细菌，真细菌和真核生物。

盐桥在蛋白质的结构和功能稳定性中起着独特的作用，尤其是在恶劣的环境下。这些盐桥如何在整个生命的各个领域促进蛋白质结构和功能的整体热力学稳定性尚不清楚。为了解决这个问题，对涉及蛋白质结构和功能的盐桥能量的统计分析是在生命的三个领域中进行的，即古细菌，真细菌和真核生物。结果表明，尽管大多数盐桥是稳定且保守的，但古细菌蛋白质的稳定性（∆∆ G _net = −5.06±3.8）远大于真细菌（∆∆ G _net = −3.7±2.9）。和eukarya（∆∆ G _net= −3.54±3.1）。与早期的古细菌研究不同，在真核生物和真细菌中，并不是我们数据集中所有埋藏的盐桥都是稳定的。埋藏的盐桥在蛋白质稳定性中起着令人惊讶的作用，在这些结构域之间清楚地观察到了它们的变异。除了桥和背景能量项的相等贡献之外，通过盐桥的稳定网络可以补偿埋入盐桥的更大的去溶剂化损失。根据蛋白质的二级结构，拓扑结构和进化，我们的观察结果表明，盐桥在序列上彼此靠近时趋于形成更多的盐桥。总的来说，我们的比较研究提供了对特定静电相互作用在不同生命领域蛋白质中的作用的见解，我们希望这对蛋白质工程和生物信息学研究有用。