5E9A

Crystal structure analysis of the cold-adamped beta-galactosidase from Rahnella sp. R3

Summary for 5E9A

• Entry DOI: 10.2210/pdb5e9a/pdb
• Descriptor: Beta-galactosidase, ZINC ION, ACETATE ION, ... (4 entities in total)
• Functional Keywords: galactosidase, tim barrel, lactose, hydrolase
• Biological source: Rahnella sp. R3
• Total number of polymer chains: 6
• Total formula weight: 482452.73

Authors

Zhang, Y.Z.,Fan, Y.T. (deposition date: 2015-10-14, release date: 2016-10-26, Last modification date: 2024-03-06)

Primary citation

Fan, Y.,Hua, X.,Zhang, Y.,Feng, Y.,Shen, Q.,Dong, J.,Zhao, W.,Zhang, W.,Jin, Z.,Yang, R.
Cloning, expression and structural stability of a cold-adapted beta-galactosidase from Rahnella sp. R3.
Protein Expr.Purif., 115:158-164, 2015

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.

PubMed: 26145832
DOI: 10.1016/j.pep.2015.07.001

Experimental method

X-RAY DIFFRACTION (2.561 Å)