Jaenicke R
Institut für Biophysik und Physikalische Biochemie, Universität Regensburg, Universitätsstrasse 31, D-93040 Regensburg, Germany.
Biochemistry (Mosc). 1998 Mar;63(3):312-21.
Proteins, due to their delicate balance of stabilizing and destabilizing interactions, are only marginally stable if physiological conditions are considered as the standard state. Enhanced intrinsic stability of "ultrastable" proteins, e.g., from extremophiles, requires only minute local structural changes. Thus, general strategies of stabilization are not available for temperature, pH, salt, or pressure adaptation. Mechanisms of enhanced thermal stability involve improved packing or docking of structural elements (domains, subunits), as well as specific local interactions, e.g., networks of ion pairs. Relating the structure and stability of eye lens crystallins (which do not undergo any turnover during the life time of an organism), point mutations, nicking and swapping of domains, grafting of linker peptides between domains, and denaturation-renaturation allowed the cumulative nature of protein stability and its relation to the hierarchy of protein structure and folding to be established. In this review, recent results for crystallins and enzymes from hyperthermophiles will be discussed as models to illustrate mechanisms of protein stabilization.
由于蛋白质稳定和不稳定相互作用之间的微妙平衡，如果将生理条件视为标准状态，它们只是勉强稳定。例如，来自极端微生物的“超稳定”蛋白质增强的内在稳定性仅需要微小的局部结构变化。因此，不存在用于温度、pH值、盐或压力适应的通用稳定策略。增强热稳定性的机制包括改善结构元件（结构域、亚基）的堆积或对接，以及特定的局部相互作用，例如离子对网络。通过研究眼晶状体晶状体蛋白（在生物体的生命周期内不发生任何周转）的结构和稳定性、点突变、结构域的切割和交换、结构域之间连接肽的嫁接以及变性-复性，得以确立蛋白质稳定性的累积性质及其与蛋白质结构和折叠层次的关系。在本综述中，将讨论来自嗜热菌的晶状体蛋白和酶的最新研究结果，作为说明蛋白质稳定机制的模型。
