| 论文题目: | Functional role of beta domain in the Thermoanaerobacter tengcongensis glucoamylase |
|---|---|
| 作者: | Li Zilong, Wei Pingying, Cheng Hairong, He Peng, Wang Qinhong, Jiang Ning* |
| 联系作者: | Jiang Ning* |
| 刊物名称: | Applied Microbiology and Biotechnology |
| 期: | 98 |
| 卷: | 5 |
| 页: | 2091-2099 |
| 年份: | 2014 |
| 影响因子: | 3.762 |
| 论文下载: | |
| 摘要: | Thermoanaerobacter tengcongensis MB4 glucoamylase (TteGA) contains a catalytic domain (CD), which is structurally similar to eukaryotic GA, and a beta domain (BD) with ambiguous function. Firstly, BD is found to be essential to TteGA activity because CD alone could not hydrolyze soluble starch. However, starch hydrolysis activity, similar to that of intact TteGA, was restored to CD in the presence of BD. Secondly, BD is found to be an important helper in the correct folding of CD because CD was mainly expressed in the inclusion bodies on its own in Escherichia coli. By contrast, intact TteGA, BD, and CD combined with BD could be expressed as soluble proteins. Additionally, BD is essential to the thermostability of TteGA because CD displayed lower thermostability compared with the intact TteGA and exhibited enhanced thermostability in the presence of BD in vitro. Truncation of TteGA or mutagenesis of the residues that participate in the interdomain interaction at its BD also led to the reduced thermostability of TteGA. |
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