A Novel Cold-Active and Alkali-Stable β-Glucosidase Gene Isolated from the Marine Bacterium Martelella mediterranea
- 235 Downloads
A β-glucosidase gene designated gluc3m was cloned through construction of a genomic library of Martelella mediterranea 2928. The gluc3m consisted of 2,496 bp and encoded a peptide of 832 amino acids that shared the greatest amino acid similarity (59%) with a β-glucosidase of family 3 glycoside hydrolase from Agrobacterium radiobacter K84. The optimum reaction temperature and pH of Gluc3M were 45 °C and 8.0, respectively. The K m and V max for p-nitrophenyl-β-d-glucopyranoside were 0.18 mg/ml and 196.08 µmol/min/mg enzyme, respectively. Gluc3M was found to be highly alkali stable, retaining 80% of its maximum enzymatic activity after treatment with pH 11.0 buffers for 24 h. Furthermore, the activity of Gluc3M improved remarkably in the presence of univalent metal ions, whereas it was inhibited in the presence of divalent ions. Gluc3M also exhibited significant activities toward various substrates including pNPGlu, pNPGal, salicin, and konjac powder. It is important to note that Gluc3M is a cold-active enzyme that showed over 50% of the maximum enzymatic activity at 4 °C. SWISS-MODEL revealed that the amino acids near the conserved domain SDW of Gluc3M contributed to the cold-active ability. Based on these characteristics, Gluc3M has the potential for use in additional studies and for industrial applications.
Keywordsβ-Glucosidase Martelella mediterranea Glycosyl hydrolase family 3 Cold active Alkaline stability
We thank Dr. Qifa Zhang for support and for helpful discussions. This study was supported by grants from the National Natural Science Foundation of China (30570057 and 30770021) and the 111 project (B07041).
- 1.Voorhorst, W. G., Eggen, R. I., Luesink, E. J., & De Vos, W. M. (1995). Journal of Bacteriology, 177, 7105–7111.Google Scholar
- 3.Planas, A. (2000). Biochimica et Biophysica Acta, 1543, 361–382.Google Scholar
- 4.Hers, H. G. (1963). The Biochemical Journal, 86, 11–16.Google Scholar
- 8.Meng, X., Shao, Z., Hong, Y., Lin, L., Li, C., & Liu, Z. (2009). Journal of Microbiology and Biotechnology, 19, 1077–1884.Google Scholar
- 10.Henrissat, B. (1991). The Biochemical Journal, 280, 309–316.Google Scholar
- 12.Keresztessy, Z., Hughes, J., Kiss, L., & Hughes, M. A. (1996). The Biochemical Journal, 314, 41–47.Google Scholar
- 18.Campbell, J. A., Davies, G. J., Bulone, V., & Henrissat, B. (1997). The Biochemical Journal, 326, 929–939.Google Scholar
- 19.Helland, R., Larsen, R. L., & Ásgeirsson, B. (2009). Biochimica et Biophysica Acta, 1794, 297–308.Google Scholar
- 31.Singh, A., & Hayashi, K. (1995). Journal of Applied Biological Chemistry, 270, 21928–21933.Google Scholar