A common protein fold and similar active site in two distinct families of beta-glycanases.
X-ray crystallography (1.64 Angstroms) of 27-406
Crystal structure of the catalytic domain of a bacterial cellulase belonging to family 5.
Crystal structure of thermostable family 5 endocellulase E1 from Acidothermus cellulolyticus in complex with cellotetraose.
X-ray crystallography (2.3 Angstroms) of mutant GLN-140.
The crystal structure of a family 5 endoglucanase mutant in complexed and uncomplexed forms reveals an induced fit activation mechanism.
Solution structure of the cellulose-binding domain of the endoglucanase Z secreted by Erwinia chrysanthemi.
X-ray crystallography (1.57 Angstroms) of 30-329
Structure of the Bacillus agaradherans family 5 endoglucanase at 1.6 A and its cellobiose complex at 2.0 A resolution.
X-ray crystallography (1.64 Angstroms) of 30-329
Snapshots along an enzymatic reaction coordinate: analysis of a retaining beta-glycoside hydrolase.
X-ray crystallography (1.75/1.95/2.1 Angstroms)
Insights into ligand-induced conformational change in Cel5A from Bacillus agaradhaerens revealed by a catalytically active crystal form.
X-ray crystallography (2.3 Angstroms) of 44-335
Type II protein secretion in gram-negative pathogenic bacteria: the study of the structure/secretion relationships of the cellulase Cel5 (formerly EGZ) from Erwinia chrysanthemi.
A novel combination of two classic catalytic schemes.
Catalytically enhanced endocellulase Cel5A from Acidothermus cellulolyticus.
This family belongs to glycosidase family-5, which has an retaining mechanism (equatorial to equatorial conformation), and also a family of 4/7 superfamily, which has got catalytic residues at the C-terminal ends of beta-4 and beta-7 on the (alpha/beta)8 barrel fold. This enzyme is composed of the N-terminal catalytic domain and the C-terminal Cellulose-binding domain. The structure of the C-terminal domain has not been determined yet. This enzyme must have the same catalytic mechanism as that of the other TIM barrel cellulases (S00203, D00501 & D00503 in EzCatDB). According to the literature [3], Glu282 and Glu162 (of 1ece) act as a nucleophile and acid-base, respectively. The catalysis proceeds through a dissociative-type (or SN1-like) mechanism, with a formation of oxocarbonium ion in the transition state, during the glycosylation of the active site. During the glycosylation, Glu282 approaches the C1 atom of the glcose, whilst Glu162 protonates the leaving group. At the second stage, or during the deglycosylation, a water molecule can be activated by a general base, Glu162. This deglycosylation also goes through the dissociative-type reaction with an oxocarbonium ion in the transition state, in which water replaced the glycosyl leaving group in the first step. Moreover, comparing the structural data with that of xylanase (E.C. 3.2.1.8) (D00479 in EzCatDB), Tyr240 (of 1ece) might stabilize the leaving nucleophile, Glu282 in deglycosylation, whilst His238 might modulate the activity of Glu162 (see [3]). On the other hand, Tyr240 might modulate the activity of the nucleophile, according to the data of the other homologous enzyme, beta-glucosidase (E.C. 3.2.1.21) (S00205 in EzCatDB).