1. A Shinella β-N-acetylglucosaminidase of glycoside hydrolase family 20 displays novel biochemical and molecular characteristics.
- Author
-
Zhou J, Song Z, Zhang R, Chen C, Wu Q, Li J, Tang X, Xu B, Ding J, Han N, and Huang Z
- Subjects
- Acetylglucosaminidase chemistry, Acetylglucosaminidase genetics, Amino Acid Sequence, Cloning, Molecular, Hydrolysis, Sequence Homology, Amino Acid, Substrate Specificity, Acetylglucosaminidase metabolism, Rhizobiaceae enzymology
- Abstract
β-N-Acetylglucosaminidases (GlcNAcases) are important for many biological functions and industrial applications. In this study, a glycoside hydrolase family 20 GlcNAcase from Shinella sp. JB10 was expressed in Escherichia coli BL21 (DE3). Compared to many GlcNAcases, the purified recombinant enzyme (rJB10Nag) exhibited a higher specificity activity (538.8 µmol min
-1 mg-1 ) or Vmax (1030.0 ± 82.1 µmol min-1 mg-1 ) toward p-nitrophenyl β-N-acetylglucosaminide and N,N'-diacetylchitobiose (specificity activity of 35.4 µmol min-1 mg-1 ) and a higher N-acetylglucosaminide tolerance (approximately 50% activity in 70.0 mM N-acetylglucosaminide). The degree of synergy on enzymatic degradation of chitin by a commercial chitinase and rJB10Nag was as high as 2.35. The enzyme was tolerant to most salts, especially 3.0-15.0% (w/v) NaCl and KCl. These biochemical characteristics make the JB10 GlcNAcase a candidate for use in many potential applications, including processing marine materials and the bioconversion of chitin waste. Furthermore, the enzyme has the highest proportions of alanine (16.5%), glycine (10.5%), and random coils (48.8%) with the lowest proportion of α-helices (24.9%) among experimentally characterized GH 20 GlcNAcases from other organisms.- Published
- 2017
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