Conserved catalytic machinery and the prediction of a common fold for several families of glycosyl hydrolases.
High-resolution native and complex structures of thermostable beta-mannanase from Thermomonospora fusca - substrate specificity in glycosyl hydrolase family 5.
A comparative study of two retaining enzymes of Trichoderma reesei: transglycosylation of oligosaccharides catalysed by the cellobiohydrolase I, Cel7A, and the beta-mannanase, Man5A.
X-RAY CRYSTALLOGRAPHY (1.4 ANGSTROMS) OF 28-371.
The three-dimensional structure of a Trichoderma reesei beta-mannanase from glycoside hydrolase family 5.
NUCLEOTIDE SEQUENCE [MRNA], TISSUE SPECIFICITY.
Characterisation of an endo-(1,4)-beta-mannanase (LeMAN4) expressed in ripening tomato fruit
Crystallization and preliminary X-ray study of alkaline mannanase from an alkaliphilic Bacillus isolate.
An elaboration on the syn-anti proton donor concept of glycoside hydrolases: electrostatic stabilisation of the transition state as a general strategy.
X-RAY CRYSTALLOGRAPHY (1.5 ANGSTROMS) OF 27-399.
Three-dimensional structure of (1,4)-beta-D-mannan mannanohydrolase from tomato fruit.
Substrate distortion by a lichenase highlights the different conformational itineraries harnessed by related glycoside hydrolases.
Investigations into the role of oxacarbenium ions in glycosylation reactions by ab initio molecular dynamics.
Three-dimensional crystal structure and enzymic characterization of beta-mannanase Man5A from blue mussel Mytilus edulis.
Microbial mannanases: an overview of production and applications.
Mechanistic insights into glycosidase chemistry.
Understanding how diverse beta-mannanases recognize heterogeneous substrates.
This enzyme belongs to the glycosidase family-5. According to the literature [11], beta-mannanase belonging to the glycosidase family-5 can be divided into three subfamilies. This enzyme, which is from eukaryote, belongs to subfamily-7. On the other hand, another enzyme group from eukaryote (S00907 in EzCatDB) belongs to subfamily-10, whereas an enzyme group from bacteria (S00906 and D00861 in EzCatDB) belongs to subfamily-8. However, the catalytic site seems to be conserved among these three subfamilies. Thus, according to the literature [8] and [11], the reaction proceeds as follows: (0) His277 (of 1rh9) may modulate the activity of acid/base, Glu04, whereas Tyr279 may modulate the activity of nucleophile, Glu318. Moreover, Arg86 may modulate the nucleophile, Glu318, as well. (1) Glu204 acts as a general acid to protonate the leaving oxygen in mannan, whereas Glu318 approaches the C1 atom of substrate mannan as a nucleophile. This process leads to an oxocarbenium-like transition-state (half-chair conformation; 4H3). The transition-state is stabilized by Asn203 (and probably Tyr279). (2) Glu318 makes a nucleophilic attack on the C1 atom of mannosyl group, to form a covalent intermediate, whereas the leaving group is cleaved from mannosyl group at subsite -1. (3) Glu204 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. Finally, the reaction completes.