The crystal structure of acidic β-galactosidase from Aspergillus oryzae

The crystal structure of the industrially importantAspergilius oryzae beta-galactosidase has been determined at 2.60 angstrom resolution. The Ao-beta-gal is a large (985 residues) monomeric multi-domain enzyme that has a catalytic (alpha/beta)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-beta-gal. Comparison of structure with other beta-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-beta-gal is also discussed. (C) 2013 Elsevier B.V. All rights reserved.