Heat stability of a tetrameric enzyme, D-glyceraldehyde-3-phosphate dehydrogenase.
Heat stability of a tetrameric enzyme, D-glyceraldehyde-3-phosphate dehydrogenase.
复制标题
四聚酶 D-甘油醛-3-磷酸脱氢酶的热稳定性。
DOI：
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发表时间：
1980
期刊：
影响因子：
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通讯作者：
J. Harris
中科院分区：
文献类型：
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作者：
J. Walker;A. Wonacott;J. Harris
来自中等嗜热芽孢杆菌（Bacillus stearothermophilus）的四聚体酶D-甘油醛-3-磷酸脱氢酶比其来自龙虾肌肉的对应物对热变性更稳定[Harris等人（1980）Eur. 108，535-547]。嗜热酶亚基之间的额外埋藏离子键对热稳定性做出重要贡献。四聚体酶的进一步稳定源自四聚体核心处的S-环之间的额外疏水相互作用。在极端嗜热菌Thermus aquaticus的酶中，它的热稳定性更高，亚基间离子对也必须发挥作用，但表面相互作用的变化似乎同样重要。因此，在亚基界面边缘的额外疏水相互作用将阻止水进入分子内部。此外，还研究了T. aquaticus酶将允许最大的表面离子对形成。其他蛋白质中表面离子对的存在与热稳定性很好地相关[Perutz，M. F. Raidt，H. 03 The Dog of the Dog（1975）255，256-258]，并在这种情况下对亚基提供一般的稳定影响。
The tetrameric enzyme D-glyceraldehyde-3-phosphate dehydrogenase from the moderate thermophile Bacillus stearothermophilus is more stable to thermal denaturation than its counterpart from lobster muscle [Harris et al. (1980) Eur. J. Biochem. 108, 535-547]. Extra buried ionic bonds between subunits of the thermophilic enzyme make an important contribution to thermal stabilisation. Further stabilisatio of the tetrameric enzyme is derived from additional hydrophobic interactions between the S-loops at the core of the tetramer. In the enzyme from the extreme thermophile Thermus aquaticus, which is even more thermostable, intersubunit ion pairs must also play a role but changes in interactions at the surface appear to be equally important. Thus additional hydrophobic interactions at the edge of subunit interfaces would prevent access of water to the interior of the molecule. Furthermore, the arrangement of charged residues on the surface of the T. aquaticus enzyme would allow maximal surface ion pair formation. The presence of surface ion pairs in other proteins correlates well with thermal stability [Perutz, M. F. and Raidt, H. (1975) Nature (Lond.) 255, 256-258] and would provide a general stabilising influence on the subunit in this case.