The crystal structure of acidic β-galactosidase from Aspergillus oryzae

Abstract

The crystal structure of the industrially important Aspergillus oryzae β-galactosidase has been determined at 2.60 Å resolution. The Ao-β-gal is a large (985 residues) monomeric multi-domain enzyme that has a catalytic (α/β)8-barrel domain. An electron density map revealed extensive N-glycosylation between the domain interfaces suggesting that the oligosaccharide-chains would have a stabilizing role for the structure of Ao-β-gal. Comparison of structure with other β-galactosidase structures of glycoside hydrolase family 35 revealed a number of hydrophobic residues, which may contribute favorably to the stabilization of the structure. The role of a high number of acidic residues in Ao-β-gal is also discussed.

Keywords: 2-methyl-2,4-pentanediol; Ao-β-gal; Aspergillus oryzae; Glycoside hydrolase; MPD; N-glycosylation; PDB; Protein Data Bank; Psp-β-gal; Tr-β-gal; crystal structure; β-galactosidase; β-galactosidase from Aspergillus oryzae; β-galactosidase from Penicllium sp.; β-galactosidase from Trichoderma reesei.