PDBsum entry 5e9a

Hydrolase

PDB id: 5e9a

Contents

Protein chains

(+ 0 more) 679 a.a.

Ligands

ACT ×6

Metals

_ZN ×6

Waters ×428

PDB id:

5e9a

Name:

Hydrolase

Title:

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

Structure:

Beta-galactosidase. Chain: a, b, c, d, e, f. Synonym: beta-gal. Engineered: yes

Source:

Rahnella sp. R3. Organism_taxid: 1591056. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.56Å R-factor: 0.200 R-free: 0.247

Authors:

Y.Z.Zhang,Y.T.Fan

Key ref:

Y.Fan et al. (2015). Cloning, expression and structural stability of a cold-adapted β-galactosidase from Rahnella sp. R3. Protein Expr Purif, 115, 158-164. PubMed id: 26145832 DOI: 10.1016/j.pep.2015.07.001

Date:

14-Oct-15 Release date: 26-Oct-16

Protein chains

A0A0B4U8I5  (A0A0B4U8I5_9GAMM) -  Beta-galactosidase from Rahnella sp. R3

Seq: 687 a.a.

Struc: 679 a.a.

Enzyme reactions

• Enzyme class: E.C.3.2.1.23 - beta-galactosidase.
• Reaction: Hydrolysis of terminal, non-reducing beta-D-galactose residues in beta-D-galactosides.

DOI no: 10.1016/j.pep.2015.07.001

Protein Expr Purif 115:158-164 (2015)

PubMed id: 26145832

Cloning, expression and structural stability of a cold-adapted β-galactosidase from Rahnella sp. R3.

Y.Fan, X.Hua, Y.Zhang, Y.Feng, Q.Shen, J.Dong, W.Zhao, W.Zhang, Z.Jin, R.Yang.

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.