嗜热栖热菌谷氨酸脱氢酶的结构揭示了离子对网络在维持极端温度下酶稳定性中的关键作用。
The structure of Pyrococcus furiosus glutamate dehydrogenase reveals a key role for ion-pair networks in maintaining enzyme stability at extreme temperatures.
作者信息
Yip K S, Stillman T J, Britton K L, Artymiuk P J, Baker P J, Sedelnikova S E, Engel P C, Pasquo A, Chiaraluce R, Consalvi V
机构信息
The Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, PO Box 594, Sheffield S10 2UH, UK.
出版信息
Structure. 1995 Nov 15;3(11):1147-58. doi: 10.1016/s0969-2126(01)00251-9.
BACKGROUND
The hyperthermophile Pyrococcus furiosus is one of the most thermostable organisms known, with an optimum growth temperature of 100 degrees C. The proteins from this organism display extreme thermostability. We have undertaken the structure determination of glutamate dehydrogenase from P. furiosus in order to gain further insights into the relationship between molecular structure and thermal stability.
RESULTS
The structure of P. furiosus glutamate dehydrogenase, a homohexameric enzyme, has been determined at 2.2 A resolution and compared with the structure of glutamate dehydrogenase from the mesophile Clostridium symbiosum.
CONCLUSIONS
Comparison of the structures of these two enzymes has revealed one major difference: the structure of the hyperthermophilic enzyme contains a striking series of ion-pair networks on the surface of the protein subunits and buried at both interdomain and intersubunit interfaces. We propose that the formation of such extended networks may represent a major stabilizing feature associated with the adaptation of enzymes to extreme temperatures.
背景
嗜热栖热菌是已知最耐热的生物体之一，其最适生长温度为100摄氏度。该生物体的蛋白质表现出极高的热稳定性。我们对嗜热栖热菌的谷氨酸脱氢酶进行了结构测定，以便进一步深入了解分子结构与热稳定性之间的关系。
结果
嗜热栖热菌谷氨酸脱氢酶是一种同六聚体酶，其结构已在2.2埃分辨率下确定，并与嗜温共生梭菌的谷氨酸脱氢酶结构进行了比较。
结论
这两种酶结构的比较揭示了一个主要差异：嗜热酶的结构在蛋白质亚基表面包含一系列显著的离子对网络，并且在结构域间和亚基间界面均有埋藏。我们提出，这种扩展网络的形成可能代表了与酶适应极端温度相关的一个主要稳定特征。
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