Arabinogalactan endo-1,4-beta-galactosidase
Structure of plant cell walls. Purification and characterization of a beta-1,4-galactanase which degrades a structural component of the primary cell walls of dicots.
Purification and characterization of Endo-1,4-À-D-galactanases from Aspergillus niger and Aspergillus aculeatus: Use in combination with arabinanases from Aspergillus niger in enzymic conversion of potato arabinogalactan
Mechanisms of enzymatic glycoside hydrolysis.
Structures and mechanisms of glycosyl hydrolases.
Evidence that galactanase A from Pseudomonas fluorescens subspecies cellulosa is a retaining family 53 glycosyl hydrolase in which E161 and E270 are the catalytic residues.
Aspergillus aculeatus beta-1,4-galactanase: substrate recognition and relations to other glycoside hydrolases in clan GH-A.
Purification and characterization of Aspergillus À-Image -galactanases acting on À-1,4- and À-1,3/6-linked arabinogalactans
X-RAY CRYSTALLOGRAPHY (2.6 ANGSTROMS), CATALYTIC ACTIVITY, GLYCOSYLATION AT ASN-111.
Structure of two fungal beta-1,4-galactanases: searching for the basis for temperature and pH optimum.
X-RAY CRYSTALLOGRAPHY (2.2 ANGSTROMS) OF 28-424 IN COMPLEX WITH CALCIUM IONS AND SUBSTRATE ANALOGS, COFACTOR.
The structure of endo-beta-1,4-galactanase from Bacillus licheniformis in complex with two oligosaccharide products.
Bifidobacterium longum endogalactanase liberates galactotriose from type I galactans.
Investigating the binding of beta-1,4-galactan to Bacillus licheniformis beta-1,4-galactanase by crystallography and computational modeling.
This enzyme belongs to glycosidase family-58, with a retaining mechanism. This enzyme is homologous to a counterpart enzyme from Bacillus licheniformis (S00912 in EzCatDB). Although the homologous enzyme binds calcium ion, this enzyme does not bind any ion. According to the literature [6], the reaction proceeds as follows: (0) Arg45 and Tyr215 modulate the pKa of catalytic nucleophile, Glu246. (1) Glu136 acts as a general acid to protonate the leaving oxygen, O4 atom at subsite +1, forming an oxocarbenium-ion-like transition-state. The transition-state is stabilized by Asn135 and Tyr215 through hydrogen bonding to the oxygen atoms at subsite -1. (SN1-like reaction) (2) Glu246 makes a nucleophilic attack on C1 atom of substrate, galactan, to form a covalent intermediate. (3) Glu136 acts as a general base to deprotonate a water molecule, to activate it. (4) The activated water makes a nucleophilic attack on the C1 atom of the covalent intermediate. Thus, the substitution reaction completes.