Two exposed amino acid residues confer thermostability on a cold shock protein
Two exposed amino acid residues confer thermostability on a cold shock protein
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DOI：
10.1038/75151
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发表时间：
2000-05
期刊：
影响因子：
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通讯作者：
D. Perl;U. Mueller;U. Heinemann;F. Schmid
中科院分区：
文献类型：
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作者：
D. Perl;U. Mueller;U. Heinemann;F. Schmid
嗜热生物产生的蛋白质具有特殊的稳定性。为了在分子水平上了解蛋白质的热稳定性，我们通过系统诱变研究了一对冷休克蛋白，其中一个是嗜温性的，另一个是嗜热性的。虽然这两个蛋白在12个位置上的序列不同，但两个表面暴露的残基导致了嗜热蛋白稳定性的增加（在70℃时增加了15.8 kJ mol−1）。11.5 kJ mol−1主要来自Arg 3的静电贡献，5.2 kJ mol−1来自Leu 66在羧基端的疏水相互作用。通过将3号和66号位置的Glu残基分别转化为精氨酸和亮氨酸，该中温性蛋白可以转化为高度热稳定的形式。因此，表面残基的变化可能为增加蛋白质的热稳定性提供了一种简单而有效的方法。
Thermophilic organisms produce proteins of exceptional stability. To understand protein thermostability at the molecular level we studied a pair of cold shock proteins, one of mesophilic and one of thermophilic origin, by systematic mutagenesis. Although the two proteins differ in sequence at 12 positions, two surface-exposed residues are responsible for the increase in stability of the thermophilic protein (by 15.8 kJ mol− 1 at 70 C). 11.5 kJ mol− 1 originate from a predominantly electrostatic contribution of Arg 3 and 5.2 kJ mol− 1 from hydrophobic interactions of Leu 66 at the carboxy terminus. The mesophilic protein could be converted to a highly thermostable form by changing the Glu residues at positions 3 and 66 to Arg and Leu, respectively. The variation of surface residues may thus provide a simple and powerful approach for increasing the thermostability of a protein.