The effect of calcium binding on the unfolding barrier: A kinetic study on homologous α-amylases

被引：26

作者：

Kumari, Arpana ^{[1
,2
]}

Rosenkranz, Tobias ^{[2
]}

Kayastha, Arvind M. ^{[1
]}

Fitter, Joerg ^{[2
]}

机构：

[1] Banaras Hindu Univ, Sch Biotechnol, Fac Sci, Varanasi 221005, Uttar Pradesh, India

[2] Forschungszentrum Julich, ISB Mol Biophys 2, D-52425 Julich, Germany

来源：

BIOPHYSICAL CHEMISTRY | 2010年 / 151卷 / 1-2期

关键词：

Alpha-amylase; Protein stability; Multi-domain protein; Calcium binding; Thermal unfolding; Eyring-plot; CONFORMATIONAL STABILITY; THERMODYNAMIC STABILITY; THERMAL-DENATURATION; PROTEINS; MECHANISM; THERMOSTABILITY; TRANSITION; INACTIVATION; ADAPTATION; RUBREDOXIN;

D O I：

10.1016/j.bpc.2010.05.005

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Extreme thermostabilities of proteins can be achieved by binding co-factors to the protein structures. For various alpha-amylases protein stabilization upon calcium binding is a well-known phenomenon. In the present study the mechanism of stabilization of three homologous alpha-amylases was investigated by measuring the unfolding kinetics with CD spectroscopy. For this purpose thermal unfolding kinetics of calcium saturated and calcium depleted enzymes were analyzed by means of Eyring-plots. The free energy change between the native and the transition state which characterized the unfolding barrier height was found to be proportional to the number of calcium ions bound to the protein structures. For the most thermostable a-amylases calcium binding caused a significant increase in the enthalpy change, which was partly compensated by increased entropy changes. (C) 2010 Elsevier B.V. All rights reserved.

引用

页码：54 / 60

页数：7

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