M00192
type: Enzyme
rlcp: p991
cath: Glycosyltransferase
cath: Immunoglobulin-like
ec: https://purl.uniprot.org/enzyme/3.2.1.4
csa: 1js4
uniprot: P26221
kegg enzyme: cellulase
kegg enzyme: endo-1,4-beta-D-glucanase
kegg enzyme: beta-1,4-glucanase
kegg enzyme: beta-1,4-endoglucan hydrolase
kegg enzyme: celluase A
kegg enzyme: cellulosin AP
kegg enzyme: endoglucanase D
kegg enzyme: alkali cellulase
kegg enzyme: cellulase A 3
kegg enzyme: celludextrinase
kegg enzyme: 9.5 cellulase
kegg enzyme: avicelase
kegg enzyme: pancellase SS
kegg enzyme: 1,4-(1,3
kegg enzyme: 1,4)-beta-D-glucan 4-glucanohydrolase
kegg pathway: Starch and sucrose metabolism
kegg substrate: Cellulose
kegg substrate: H2O
kegg substrate: Lichenin
kegg substrate: beta-D-Glucan
kegg product: Cellobiose
kegg product: Cellulose
pdb: 1js4A01
pdb: 1js4B01
pdb: 1tf4A01
pdb: 1tf4B01
pdb: 3tf4A01
pdb: 3tf4B01
pdb: 4tf4A01
pdb: 4tf4B01
pdb: 1js4A02
pdb: 1js4B02
pdb: 1tf4A02
pdb: 1tf4B02
pdb: 3tf4A02
pdb: 3tf4B02
pdb: 4tf4A02
pdb: 4tf4B02
pdb bound state: Unbound
  compound: Cellulose
  pdb: 1js4A01
pdb bound state: Unbound
  compound: Cellulose
  pdb: 1js4B01
pdb bound state: Unbound
  compound: Cellulose
  pdb: 1tf4A01
pdb bound state: Unbound
  compound: Cellulose
  pdb: 1tf4B01
pdb bound state: Unbound
  compound: Cellulose
  pdb: 3tf4A01
pdb bound state: Unbound
  compound: Cellulose
  pdb: 3tf4B01
pdb bound state: Unbound
  compound: Cellulose
  pdb: 4tf4A01
pdb bound state: Unbound
  compound: Cellulose
  pdb: 4tf4B01
pdb bound state: Unbound
  compound: Cellulose
  pdb: 1js4A02
pdb bound state: Unbound
  compound: Cellulose
  pdb: 1js4B02
pdb bound state: Unbound
  compound: Cellulose
  pdb: 1tf4A02
pdb bound state: Unbound
  compound: Cellulose
  pdb: 1tf4B02
pdb bound state: Unbound
  compound: Cellulose
  pdb: 3tf4A02
pdb bound state: Unbound
  compound: Cellulose
  pdb: 3tf4B02
pdb bound state: Unbound
  compound: Cellulose
  pdb: 4tf4A02
pdb bound state: Unbound
  compound: Cellulose
  pdb: 4tf4B02
pdb bound state: Unbound
  compound: Lichenin
  pdb: 1js4A01
pdb bound state: Unbound
  compound: Lichenin
  pdb: 1js4B01
pdb bound state: Unbound
  compound: Lichenin
  pdb: 1tf4A01
pdb bound state: Unbound
  compound: Lichenin
  pdb: 1tf4B01
pdb bound state: Unbound
  compound: Lichenin
  pdb: 3tf4A01
pdb bound state: Unbound
  compound: Lichenin
  pdb: 3tf4B01
pdb bound state: Unbound
  compound: Lichenin
  pdb: 4tf4A01
pdb bound state: Unbound
  compound: Lichenin
  pdb: 4tf4B01
pdb bound state: Unbound
  compound: Lichenin
  pdb: 1js4A02
pdb bound state: Unbound
  compound: Lichenin
  pdb: 1js4B02
active site residues resources: Roles of the catalytic domain and two cellulose binding domains of Thermomonospora fusca E4 in cellulose hydrolysis.
active site residues resources: http://ezcatdb.cbrc.jp/EzCatDB/reference/M00192#5
references: Identification of two functionally different classes of exocellulases.
references: Structure and mechanism of endo/exocellulase E4 from Thermomonospora fusca.
references: Roles of the catalytic domain and two cellulose binding domains of Thermomonospora fusca E4 in cellulose hydrolysis.
references: Kinetic studies of Thermobifida fusca Cel9A active site mutant enzymes.
comment: 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.

Glycosyltransferase
type: Cath
references: http://www.cathdb.info/version/latest/superfamily/1.50.10.10
catalytic domain: index.html

Immunoglobulin-like
type: Cath
references: http://www.cathdb.info/version/latest/superfamily/2.60.40.710

Immunoglobulin-like
type: Cath
references: http://www.cathdb.info/version/latest/superfamily/2.60.40.30

Immunoglobulin-like
type: Cath
references: http://www.cathdb.info/version/latest/superfamily/2.60.40.290

Starch and sucrose metabolism
type: KeggPathway
references: KEGG:MAP00500

Cellulose
type: KeggSubstrate
references: KEGG:C00760
compound type: polysaccharide
type: KeggProduct

H2O
type: KeggSubstrate
references: KEGG:C00001
compound type: H2O
references: CHEBI:15377
references: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi

Lichenin
type: KeggSubstrate
references: KEGG:C00478
compound type: carbohydrate
references: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi

beta-D-Glucan
type: KeggSubstrate
references: KEGG:C00551
compound type: polysaccharide
references: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi

Cellobiose
type: KeggProduct
references: KEGG:C00185
compound type: polysaccharide
references: CHEBI:17057
references: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi

1js4A01
type: Pdb
references: 1js4
references: http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl
references: PDB:1js4
catalytic residue: ASP 55;ASP 58;HIS 125;TYR 206;GLU 424

1js4B01
type: Pdb
references: 1js4
references: http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl
references: PDB:1js4
catalytic residue: ASP 55;ASP 58;HIS 125;TYR 206;GLU 424

1tf4A01
type: Pdb
references: 1tf4
references: http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl
references: PDB:1tf4
catalytic residue: ASP 55;ASP 58;HIS 125;TYR 206;GLU 424

1tf4B01
type: Pdb
references: 1tf4
references: http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl
references: PDB:1tf4
catalytic residue: ASP 55;ASP 58;HIS 125;TYR 206;GLU 424

3tf4A01
type: Pdb
references: 3tf4
references: http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl
references: PDB:3tf4
catalytic residue: ASP 55;ASP 58;HIS 125;TYR 206;GLU 424

3tf4B01
type: Pdb
references: 3tf4
references: http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl
references: PDB:3tf4
catalytic residue: ASP 55;ASP 58;HIS 125;TYR 206;GLU 424

4tf4A01
type: Pdb
references: 4tf4
references: http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl
references: PDB:4tf4
catalytic residue: ASP 55;ASP 58;HIS 125;TYR 206;GLU 424

4tf4B01
type: Pdb
references: 4tf4
references: http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl
references: PDB:4tf4
catalytic residue: ASP 55;ASP 58;HIS 125;TYR 206;GLU 424

Identification of two functionally different classes of exocellulases.
type: BibliographicResource
references: http://www.ncbi.nlm.nih.gov/pubmed/8555231
journal: Biochemistry
volume: 35
pages: 586-92
published year: 1996
authors:
  item: Barr BK
  item: Hsieh YL
  item: Ganem B
  item: Wilson DB

Structure and mechanism of endo/exocellulase E4 from Thermomonospora fusca.
type: BibliographicResource
comment: X-RAY CRYSTALLOGRAPHY (1.9 ANGSTROMS) OF 47-651
medline id: 9334746
references: http://www.ncbi.nlm.nih.gov/pubmed/9334746
journal: Nat Struct Biol
volume: 4
pages: 810-8
published year: 1997
authors:
  item: Sakon J
  item: Irwin D
  item: Wilson DB
  item: Karplus PA
references: http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl
references: P26221

Roles of the catalytic domain and two cellulose binding domains of Thermomonospora fusca E4 in cellulose hydrolysis.
type: BibliographicResource
references: http://www.ncbi.nlm.nih.gov/pubmed/9537366
journal: J Bacteriol
volume: 180
pages: 1709-14
published year: 1998
authors:
  item: Irwin D
  item: Shin DH
  item: Zhang S
  item: Barr BK
  item: Sakon J
  item: Karplus PA
  item: Wilson DB

Kinetic studies of Thermobifida fusca Cel9A active site mutant enzymes.
type: BibliographicResource
references: http://www.ncbi.nlm.nih.gov/pubmed/15274620
journal: Biochemistry
volume: 43
pages: 9655-63
published year: 2004
authors:
  item: Zhou W
  item: Irwin DC
  item: Escovar-Kousen J
  item: Wilson DB

Analogue
compound: Cellobiose
pdb: 1js4B01
ligand het code: GLC

Analogue
compound: Cellobiose
pdb: 3tf4A01
ligand het code: GLC

Analogue
compound: Cellobiose
pdb: 3tf4B01
ligand het code: GLC

Analogue
compound: Cellobiose
pdb: 4tf4A01
ligand het code: GLC-GLC

Analogue
compound: Cellobiose
pdb: 4tf4B01
ligand het code: GLC-GLC

Analogue
compound: Cellulose
pdb: 1js4A01
ligand het code: GLC-GLC-GLC

Analogue
compound: Cellulose
pdb: 1js4B01
ligand het code: GLC-GLC

Analogue
compound: Cellulose
pdb: 3tf4A01
ligand het code: GLC-GLC-GLC

Analogue
compound: Cellulose
pdb: 3tf4B01
ligand het code: GLC-GLC-GLC

Analogue
compound: Cellulose
pdb: 4tf4A01
ligand het code: GLC-GLC-GLC-GLC

Analogue
compound: Cellulose
pdb: 4tf4B01
ligand het code: GLC-GLC-GLC-GLC

ReferenceForCatalyticMechanism
reference index: 2
reference section: Fig.4, p.814-815

ReferenceForCatalyticMechanism
reference index: 4
reference section: p.9662