EFFECTS OF MAGNESIUM-SULFATE ON AN UNFOLDING STEP OF HUMAN CYANOMET MYOGLOBIN

被引：3

作者：

KONNO, T

MORISHIMA, I

机构：

[1] Division of Molecular Engineering, Graduate School of Engineering, Kyoto University

来源：

BIOPHYSICAL JOURNAL | 1993年 / 65卷 / 02期

关键词：

D O I：

10.1016/S0006-3495(93)81123-8

中图分类号：

Q6 [生物物理学];

学科分类号：

071011 ;

摘要：

The effects of magnesium sulfate (MgSO4) on an unfolding step of human cyanomet myoglobin (Mb) were examined for wild-type and three L --> A mutant Mbs. The unfolding was induced at acidic pH (3.6-4.5) with various concentrations of MgSO4 (0-2 M). The monophasic process was monitored by visible absorption spectroscopy. We observed quite nonlinear DELTAG(double dagger)-[MgSO4] relations for all the Mbs. DELTAG(double dagger)-[MgCl2] relations were also determined for a comparative study. Thermodynamic evaluation of the results indicated that an upward reflection of DELTAG(double dagger)-[MgSO4] relations in high [MgSO4] is caused by the strong Hofmeister effect of the salt. Results obtained for three mutants (L29A, L72A, and L104A) at pH 4.0 and 4.5 were consistent with our previous observation that the structure of the transition state is determined by the stability of Mb cores in the balance with the pH conditions of unfolding (T. Konno and 1. Morishima. 1993. Biochim. Biophys. Acta. 1162:93-98).

引用

页码：907 / 911

页数：5

共 20 条

[1]

ADACHI S, 1992, J BIOL CHEM, V267, P12614

[2] WHY PREFERENTIAL HYDRATION DOES NOT ALWAYS STABILIZE THE NATIVE STRUCTURE OF GLOBULAR-PROTEINS [J].