Download MendeleyCloning, expression and structural stability of a cold-adapted beta-galactosidase from Rahnella sp. R3.
Fan, Y., Hua, X., Zhang, Y., Feng, Y., Shen, Q., Dong, J., Zhao, W., Zhang, W., Jin, Z., Yang, R.(2015) Protein Expr Purif 115: 158-164
- PubMed: 26145832
- DOI: https://doi.org/10.1016/j.pep.2015.07.001
- Primary Citation of Related Structures:
5E9A - PubMed Abstract:
A novel gene was isolated for the first time from a psychrophilic gram-negative bacterium Rahnella sp. R3. The gene encoded a cold-adapted β-galactosidase (R-β-Gal). Recombinant R-β-Gal was expressed in Escherichia coli BL21 (DE3), purified and characterized. R-β-gal belongs to the glycosyl hydrolase family 42. Circular dichroism spectrometry of the structural stability of R-β-Gal with respect to temperature indicated that the secondary structures of the enzyme were stable to 45°C. In solution, the enzyme was a homo-trimer and was active at temperatures as low as 4°C. The enzyme did not require the presence of metal ions to be active, but Mg(2+), Mn(2+), and Ca(2+) enhanced its activity slightly, whereas Fe(3+), Zn(2+) and Al(3+) appeared to inactive it. The purified enzyme displayed K(m) values of 6.5 mM for ONPG and 2.2mM for lactose at 4°C. These values were lower than the corresponding K(m)s reported for other cold-adapted β-Gals.
Organizational Affiliation:
State Key Laboratory of Food Science and Technology, Jiangnan University, 214122 Wuxi, China; School of Food Science and Technology, Jiangnan University, 214122 Wuxi, China. Electronic address: yilin58299@163.com.
