EzCatDB: M00192
Related links:    PDB-formatted query search system Fasta-formatted query search system Fasta-formatted query search system

DB codeM00192
RLCP classification1.30.5050.991 : Hydrolysis
CATH domainDomain 11.50.10.10 : GlycosyltransferaseCatalytic domain
Domain 22.60.40.710 : Immunoglobulin-like
Domain 32.60.40.30 : Immunoglobulin-like
Domain 42.60.40.290 : Immunoglobulin-like
E.C.3.2.1.4
CSA1js4

CATH domainRelated DB codes (homologues)
1.50.10.10 : GlycosyltransferaseS00531,S00048,S00845,D00167,D00500,T00245,T00246
2.60.40.290 : Immunoglobulin-likeM00219,D00479,D00502,D00504,M00026
2.60.40.30 : Immunoglobulin-likeM00124,M00134,M00129,M00136,M00149
2.60.40.710 : Immunoglobulin-likeT00246

Enzyme Name
UniProtKBKEGG

P26221
Protein nameEndoglucanase E-4cellulase
endo-1,4-beta-D-glucanase
beta-1,4-glucanase
beta-1,4-endoglucan hydrolase
celluase A
cellulosin AP
endoglucanase D
alkali cellulase
cellulase A 3
celludextrinase
9.5 cellulase
avicelase
pancellase SS
1,4-(1,3
1,4)-beta-D-glucan 4-glucanohydrolase
SynonymsEC 3.2.1.4
Endo-1,4-beta-glucanase E-4
Cellulase E-4
Cellulase E4
PfamPF00553 (CBM_2)
PF00942 (CBM_3)
PF00041 (fn3)
PF00759 (Glyco_hydro_9)
[Graphical view]
CAZyGH9 (Glycoside Hydrolase Family)

KEGG pathways
MAP codePathways
MAP00500Starch and sucrose metabolism

UniProtKB:Accession NumberP26221
Entry nameGUN4_THEFU
ActivityEndohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans.
Subunit
Subcellular location
Cofactor

Compound table: links to PDB-related databases & PoSSuM

SubstratesProducts
KEGG-idC00760C00001C00478C00551C00185C00760
CompoundCelluloseH2OLicheninbeta-D-GlucanCellobioseCellulose
TypepolysaccharideH2Ocarbohydratepolysaccharidepolysaccharidepolysaccharide
ChEBI
15377


17057

PubChem
962
22247451
439241
46173706
439178

              
1js4A01Unbound UnboundUnboundUnboundAnalogue:GLC-GLC-GLC
1js4B01Unbound UnboundUnboundAnalogue:GLCAnalogue:GLC-GLC
1tf4A01Unbound UnboundUnboundUnboundUnbound
1tf4B01Unbound UnboundUnboundUnboundUnbound
3tf4A01Unbound UnboundUnboundAnalogue:GLCAnalogue:GLC-GLC-GLC
3tf4B01Unbound UnboundUnboundAnalogue:GLCAnalogue:GLC-GLC-GLC
4tf4A01Unbound UnboundUnboundAnalogue:GLC-GLCAnalogue:GLC-GLC-GLC-GLC
4tf4B01Unbound UnboundUnboundAnalogue:GLC-GLCAnalogue:GLC-GLC-GLC-GLC
1js4A02Unbound UnboundUnboundUnboundUnbound
1js4B02Unbound UnboundUnboundUnboundUnbound
1tf4A02Unbound UnboundUnboundUnboundUnbound
1tf4B02Unbound UnboundUnboundUnboundUnbound
3tf4A02Unbound UnboundUnboundUnboundUnbound
3tf4B02Unbound UnboundUnboundUnboundUnbound
4tf4A02Unbound UnboundUnboundUnboundUnbound
4tf4B02Unbound UnboundUnboundUnboundUnbound

Active-site residues
resource
literature [2], [4]
pdbCatalytic residues
         
1js4A01ASP  55;ASP  58;HIS 125;TYR 206;GLU 424
1js4B01ASP  55;ASP  58;HIS 125;TYR 206;GLU 424
1tf4A01ASP  55;ASP  58;HIS 125;TYR 206;GLU 424
1tf4B01ASP  55;ASP  58;HIS 125;TYR 206;GLU 424
3tf4A01ASP  55;ASP  58;HIS 125;TYR 206;GLU 424
3tf4B01ASP  55;ASP  58;HIS 125;TYR 206;GLU 424
4tf4A01ASP  55;ASP  58;HIS 125;TYR 206;GLU 424
4tf4B01ASP  55;ASP  58;HIS 125;TYR 206;GLU 424
1js4A02 
1js4B02 
1tf4A02 
1tf4B02 
3tf4A02 
3tf4B02 
4tf4A02 
4tf4B02 

References for Catalytic Mechanism
ReferencesSectionsNo. of steps in catalysis
[2]Fig.4, p.814-815
[4]p.9662

references
[1]
PubMed ID8555231
JournalBiochemistry
Year1996
Volume35
Pages586-92
AuthorsBarr BK, Hsieh YL, Ganem B, Wilson DB
TitleIdentification of two functionally different classes of exocellulases.
[2]
CommentsX-RAY CRYSTALLOGRAPHY (1.9 ANGSTROMS) OF 47-651
Medline ID9334746
PubMed ID9334746
JournalNat Struct Biol
Year1997
Volume4
Pages810-8
AuthorsSakon J, Irwin D, Wilson DB, Karplus PA
TitleStructure and mechanism of endo/exocellulase E4 from Thermomonospora fusca.
Related PDB1js4,1tf4,3tf4,4tf4
Related UniProtKBP26221
[3]
PubMed ID9537366
JournalJ Bacteriol
Year1998
Volume180
Pages1709-14
AuthorsIrwin D, Shin DH, Zhang S, Barr BK, Sakon J, Karplus PA, Wilson DB
TitleRoles of the catalytic domain and two cellulose binding domains of Thermomonospora fusca E4 in cellulose hydrolysis.
[4]
PubMed ID15274620
JournalBiochemistry
Year2004
Volume43
Pages9655-63
AuthorsZhou W, Irwin DC, Escovar-Kousen J, Wilson DB
TitleKinetic studies of Thermobifida fusca Cel9A active site mutant enzymes.

comments
This enzyme belongs to the glycosidase family-9.
Although this enzyme binds two calcium ions, they are not involved in catalysis at all.
According to the literature [2], this enzyme hydrolyzes cellulose with inversion of configuration at the anomeric carbon. The reaction mechanism of this enzyme requires a general acid to protonate the glycosidic oxygen and a general base to extract a proton from a nucleophilic water which attacks the anomeric carbon.
The catalytic mechanism seems to be similar to that of beta-amylase (D00166 in EzCatDB). The reaction proceeds as follows (see [2] & [4]):
(0) Tyr206 modulates the pKa of Asp55, whereas His125 modulates the pKa of Asp58.
(1) Glu424 acts as a general acid to protonate the leaving group, the glycosidic oxygen, forming an oxocarbonium ion in the transition state. (SN1-like reaction)
(2) Both Asp55 and Asp58 act as general bases to deprotonate the nucleophilic water. (Here, Asp58 seems more likely to be the base.)
(3) The activated water makes a nucleophilic attack on the anomeric carbon to complete the reaction.

createdupdated
2004-03-232009-02-26


Copyright: Nozomi Nagano, JST & CBRC-AIST
Funded by PRESTO/Japan Science and Technology Corporation (JST) (December 2001 - November 2004)
Funded by Grant-in-Aid for Publication of Scientific Research Results/Japan Society for the Promotion of Science (JSPS) (April 2005 - March 2006)
Funded by Grant-in-Aid for Scientific Research (B)/Japan Society for the Promotion of Science (JSPS) (April 2005 - March 2008)
Funded by BIRD/Japan Science and Technology Corporation (JST) (September 2005 - September 2008)
Funded by BIRD/Japan Science and Technology Corporation (JST) (October 2007 - September 2010)
Funded by Grant-in-Aid for Publication of Scientific Research Results/Japan Society for the Promotion of Science (JSPS) (April 2011 - March 2012)
Funded by Grant-in-Aid for Publication of Scientific Research Results/Japan Society for the Promotion of Science (JSPS) (April 2012 - March 2013)
Supported by the commission for the Development of Artificial Gene Synthesis Technology for Creating Innovative Biomaterial from the Ministry of Economy, Trade and Industry (METI) (October 2012 - )
© Biotechnology Research Institute for Drug Discovery, AIST, 2015-2016 All Rights Reserved.
© Computational Biology Research Center, AIST, 2004-2016 All Rights Reserved.