通过化学交联实现解淀粉芽孢杆菌α-淀粉酶的热稳定性

Thermostabilization of Bacillus amyloliquefaciens alpha-amylase by chemical cross-linking.

作者信息

Habibi Azadeh Ebrahim, Khajeh Khosro, Naderi-Manesh Hossein, Ranjbar Bijan, Nemat-Gorgani Mohsen

机构信息

Institute of Biochemistry and Biophysics, University of Tehran, P.O. Box 13145-1384, Tehran, Iran.

出版信息

J Biotechnol. 2006 Jun 10;123(4):434-42. doi: 10.1016/j.jbiotec.2005.12.017. Epub 2006 Jan 30.

DOI:10.1016/j.jbiotec.2005.12.017

PMID:16446001

Abstract

Chemical cross-linking of a mesophilic alpha-amylase from Bacillus amyloliquefaciens (BAA) was carried out. Intra-molecular cross-links between lysine residues upon treatment of the enzyme with ethylene glycol bis(succinic acid N-hydroxy succinimide ester) resulted in enhancement of thermostability as indicated by irreversible thermoinactivation experiments. Enhancement of thermostability coincided with a dramatic protection against aggregation, combined with a decrease in surface hydrophobicity. Deamidation, another important mechanism of irreversible thermoinactivation, was also diminished upon modification. While no significant changes in the kinetic parameters are evident, rigidification of the protein structure is suggested by circular dichroism (CD) and fluorescence studies.

摘要

对解淀粉芽孢杆菌（BAA）来源的嗜温α-淀粉酶进行了化学交联。用乙二醇双（琥珀酸N-羟基琥珀酰亚胺酯）处理该酶后，赖氨酸残基之间形成分子内交联，不可逆热失活实验表明热稳定性增强。热稳定性的增强与对聚集的显著保护作用同时出现，并伴随着表面疏水性的降低。脱酰胺作用是不可逆热失活的另一个重要机制，修饰后也有所减弱。虽然动力学参数没有明显变化，但圆二色性（CD）和荧光研究表明蛋白质结构发生了刚性化。