Publication Abstract from PubMed
The crystal structure of beta-galactosidase from Bacillus circulans (BgaC) was determined at 1.8A resolution. The overall structure of BgaC consists of three distinct domains, which are the catalytic domain with a TIM-barrel structure and two all-beta 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 beta(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 alpha-d-galactopyranosyl fluoride (alphaGalF) to different beta-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 beta1-3-linked key galactosides like galacto-N-biose or lacto-N-biose.
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.,Henze M, You DJ, Kamerke C, Hoffmann N, Angkawidjaja C, Ernst S, Pietruszka J, Kanaya S, Elling L J Biotechnol. 2014 Jul 14. pii: S0168-1656(14)00337-X. doi:, 10.1016/j.jbiotec.2014.07.003. PMID:25034434[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
