4MAD

Crystal structure of beta-galactosidase C (BgaC) from Bacillus circulans ATCC 31382

Summary for 4MAD

• Entry DOI: 10.2210/pdb4mad/pdb
• Descriptor: Beta-galactosidase, 2-(2-METHOXYETHOXY)ETHANOL (3 entities in total)
• Functional Keywords: beta-galactosidase, bgac, gh-a, (b/a)8/gh, family 35, hydrolase
• Biological source: Bacillus circulans
• Total number of polymer chains: 2
• Total formula weight: 137518.89

Authors

Kamerke, C.,You, D.J.,Kanaya, S.,Elling, L. (deposition date: 2013-08-16, release date: 2014-08-27, Last modification date: 2023-11-08)

Primary citation

Henze, M.,You, D.J.,Kamerke, C.,Hoffmann, N.,Angkawidjaja, C.,Ernst, S.,Pietruszka, J.,Kanaya, S.,Elling, L.
Rational design of a glycosynthase by the crystal structure of beta-galactosidase from Bacillus circulans (BgaC) and its use for the synthesis of N-acetyllactosamine type 1 glycan structures.
J.Biotechnol., 191:78-85, 2014

PubMed Abstract: The crystal structure of β-galactosidase from Bacillus circulans (BgaC) was determined at 1.8Å resolution. The overall structure of BgaC consists of three distinct domains, which are the catalytic domain with a TIM-barrel structure and two all-β domains (ABDs). The main-chain fold and steric configurations of the acidic and aromatic residues at the active site were very similar to those of Streptococcus pneumoniae β(1,3)-galactosidase BgaC in complex with galactose. The structure of BgaC was used for the rational design of a glycosynthase. BgaC belongs to the glycoside hydrolase family 35. The essential nucleophilic amino acid residue has been identified as glutamic acid at position 233 by site-directed mutagenesis. Construction of the active site mutant BgaC-Glu233Gly gave rise to a galactosynthase transferring the sugar moiety from α-d-galactopyranosyl fluoride (αGalF) to different β-linked N-acetylglucosamine acceptor substrates in good yield (40-90%) with a remarkably stable product formation. Enzymatic syntheses with BgaC-Glu233Gly afforded the stereo- and regioselective synthesis of β1-3-linked key galactosides like galacto-N-biose or lacto-N-biose.

PubMed: 25034434
DOI: 10.1016/j.jbiotec.2014.07.003

Experimental method

X-RAY DIFFRACTION (1.8 Å)