Characterization of a NaCl-tolerant β-N-acetylglucosaminidase from Sphingobacterium sp. HWLB1

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• 作者：Junpei Zhou ; Zhifeng Song ; Rui Zhang ; Limei Ding ; Qian Wu ; Junjun Li…
• 刊名：Extremophiles
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：20
• 期：4
• 页码：547-557
• 全文大小：2,467 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Microbiology
  Biotechnology
  Ecology
  
• 出版者：Springer Japan
• ISSN：1433-4909
• 卷排序：20

文摘

β-N-Acetylglucosaminidases serve important biological functions and various industrial applications. A glycoside hydrolase family 3 β-N-acetylglucosaminidase gene was cloned from Sphingobacterium sp. HWLB1 and expressed in Escherichia coli BL21 (DE3). The purified recombinant enzyme (rNag3HWLB1) showed apparent optimal activity at pH 7.0 and 40 °C. In the presence of 0.5–20.0 % (w/v) NaCl, the activity and stability of rNag3HWLB1 were slightly affected or not affected. The enzyme could even retain 73.6 % activity when 30.0 % (w/v) NaCl was added to the reaction mixture. The half-life of the enzyme was approximately 10 min at 37 °C without the addition of NaCl. However, the enzyme was stable at 37 °C in the presence of 3.0 % (w/v) NaCl. A large negatively charged surface in the catalytic pocket of the enzyme was observed and might contribute to NaCl tolerance and thermostability improvement. The degree of synergy between a commercial endochitinase and rNag3HWLB1 on chitin enzymatic degradation ranged from 3.11 to 3.74. This study is the first to report the molecular and biochemical properties of a NaCl-tolerant β-N-acetylglucosaminidase.Keywordsβ-N-AcetylglucosaminidaseNaCl toleranceThermostabilitySynergistic actionNegatively charged surfaceSphingobacterium