1. Characterization of a NaCl-tolerant β-N-acetylglucosaminidase from Sphingobacterium sp. HWLB1.
- Author
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Zhou J, Song Z, Zhang R, Ding L, Wu Q, Li J, Tang X, Xu B, Ding J, Han N, and Huang Z
- Subjects
- Acetylglucosaminidase chemistry, Bacterial Proteins chemistry, Catalytic Domain, Chitin metabolism, Enzyme Stability, Hot Temperature, Hydrogen-Ion Concentration, Sodium Chloride, Sphingobacterium genetics, Acetylglucosaminidase metabolism, Bacterial Proteins metabolism, Salt Tolerance, Sphingobacterium enzymology
- Abstract
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.
- Published
- 2016
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