Osmolyte effect on the stability and folding of a hyperthermophilic protein
Osmolyte effect on the stability and folding of a hyperthermophilic protein
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DOI：
10.1002/prot.21660
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发表时间：
2008-04-01
影响因子：
2.9
通讯作者：
Kanaya, Shigenori
中科院分区：
文献类型：
--
作者：
Mukaiyama, Atsushi;Koga, Yuichi;Kanaya, Shigenori
已知蛋白质通过天然存在的渗透剂如氨基酸、糖和甲胺来稳定。在这里，我们研究了三甲基胺-N-氧化物（TMAO）对核糖核酸酶HII的构象稳定性的影响，从一个超嗜热菌，热球菌Kodakaraensis（TK-RNase HII），这本身就具有很高的构象稳定性。热和盐酸胍诱导的展开实验表明，在0.5M TMAO的存在下，Tk-RNase HII的构象稳定性高于在没有TMAO在所有检查的温度。TMAO影响Tk-RNase HII的去折叠和重折叠动力学的相似程度。这些结果表明，蛋白质是普遍稳定的渗压剂，无论其鲁棒性，并提出了一种稳定的渗压剂，所造成的不利的相互作用的渗压剂与蛋白质骨架在变性状态下的机制。我们的研究结果还表明，基本的蛋白质折叠原则是不依赖于蛋白质的稳定性和进化。
Proteins are known to be stabilized by naturally occurring osmolytes such as amino acids, sugars, and methylamines. Here, we examine the effect of trimethylamine-N-oxide (TMAO) on the conformational stability of ribonuclease HII from a hyperthermophile, Thermococcus kodakaraensis (Tk-RNase HII), which inherently possesses high conformational stability. Heat- and guanidine hydrochloride-induced unfolding experiments demonstrated that the conformational stability of Tk-RNase HII in the presence of 0.5M TMAO was higher than that in the absence of TMAO at all examined temperatures. TMAO affected the unfolding and refolding kinetics of Tk-RNase HII to a similar extent. These results indicate that proteins are universally stabilized by osmolytes, regardless of their robustness, and suggest a stabilization mechanism by osmolytes, caused by the unfavorable interaction of osmolytes with protein backbones in the denatured state. Our results also imply that the basic protein folding principle is not dependent on protein stability and evolution.