DB code: S00125

RLCP classification 1.30.5100.2 : Hydrolysis
CATH domain 2.40.40.10 : Barwin-like endoglucanases Catalytic domain
E.C. 3.2.1.4
CSA 2eng
M-CSA 2eng
MACiE

CATH domain Related DB codes (homologues)

Uniprot Enzyme Name
UniprotKB Protein name Synonyms CAZy Pfam
P43316 Endoglucanase-5
EC 3.2.1.4
Endoglucanase V
Endo-1,4-beta-glucanase V
EG V
Cellulase V
CBM1 (Carbohydrate-Binding Module Family 1)
GH45 (Glycoside Hydrolase Family 45)
PF02015 (Glyco_hydro_45)
[Graphical View]

KEGG enzyme name
cellulase
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

UniprotKB: Accession Number Entry name Activity Subunit Subcellular location Cofactor
P43316 GUN5_HUMIN Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans.

KEGG Pathways
Map code Pathways E.C.
MAP00500 Starch and sucrose metabolism

Compound table
Substrates Products Intermediates
KEGG-id C00760 C00001 C00760 C00185
E.C.
Compound Cellulose H2O Cellulose Cellobiose
Type polysaccharide H2O polysaccharide polysaccharide
ChEBI 15377
17057
PubChem 22247451
962
439178
1hd5A Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
2engA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
3engA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Bound:CBI
4engA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Analogue:CTR_1 Analogue:CTR_1

Reference for Active-site residues
resource references E.C.
Swiss-prot;P43316

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
1hd5A Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 10;ASP 122
2engA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 10;ASP 121
3engA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 10;ASP 121
4engA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ;ASP 121 mutation D10N

References for Catalytic Mechanism
References Sections No. of steps in catalysis
[2]
p.364
[3]
p.224-225
[4]
Fig.5, Fig.9, p.16218-16220
[5]
p.14-16

References
[1]
Resource
Comments
Medline ID
PubMed ID 8223652
Journal Eur J Biochem
Year 1993
Volume 217
Pages 947-53
Authors Schou C, Rasmussen G, Kaltoft MB, Henrissat B, Schulein M
Title Stereochemistry, specificity and kinetics of the hydrolysis of reduced cellodextrins by nine cellulases.
Related PDB
Related UniProtKB
[2]
Resource
Comments X-RAY CRYSTALLOGRAPHY (1.6 ANGSTROMS).
Medline ID 93390621
PubMed ID 8377830
Journal Nature
Year 1993
Volume 365
Pages 362-4
Authors Davies GJ, Dodson GG, Hubbard RE, Tolley SP, Dauter Z, Wilson KS, Hjort C, Mikkelsen JM, Rasmussen G, Schulein M
Title Structure and function of endoglucanase V.
Related PDB
Related UniProtKB P43316
[3]
Resource
Comments
Medline ID
PubMed ID 7984103
Journal Mol Microbiol
Year 1994
Volume 13
Pages 219-28
Authors Saloheimo A, Henrissat B, Hoffren AM, Teleman O, Penttila M
Title A novel, small endoglucanase gene, egl5, from Trichoderma reesei isolated by expression in yeast.
Related PDB
Related UniProtKB
[4]
Resource
Comments X-RAY CRYSTALLOGRAPHY (1.9 ANGSTROMS).
Medline ID 96101453
PubMed ID 8519779
Journal Biochemistry
Year 1995
Volume 34
Pages 16210-20
Authors Davies GJ, Tolley SP, Henrissat B, Hjort C, Schulein M
Title Structures of oligosaccharide-bound forms of the endoglucanase V from Humicola insolens at 1.9 A resolution.
Related PDB
Related UniProtKB P43316
[5]
Resource
Comments X-RAY CRYSTALLOGRAPHY (1.5 ANGSTROMS).
Medline ID
PubMed ID
Journal Acta Crystallogr D Biol Crystallogr
Year 1996
Volume 52
Pages 7-17
Authors Davies GJ, Dodson GG, Moore MH, Tolley SP, Dauter Z, Wilson KS, Rasmussen G, Schuelein M
Title Structure determination and refinement of the Humicola insolens endoglucanase V at 1.5-A resolution.
Related PDB 2eng 3eng 4eng
Related UniProtKB P43316
[6]
Resource
Comments
Medline ID
PubMed ID 10424462
Journal Electrophoresis
Year 1999
Volume 20
Pages 1403-11
Authors Attanasio F, Bruschi M, Candiano G, Galletto R, Musante L, Schulein M, Rialdi G
Title Analytical titration curves of glycosyl hydrolase Cel45 by combined isoelectric focusing-electrophoresis.
Related PDB
Related UniProtKB
[7]
Resource
Comments
Medline ID
PubMed ID 10368289
Journal Structure Fold Des
Year 1999
Volume 7
Pages 227-36
Authors Castillo RM, Mizuguchi K, Dhanaraj V, Albert A, Blundell TL, Murzin AG
Title A six-stranded double-psi beta barrel is shared by several protein superfamilies.
Related PDB
Related UniProtKB
[8]
Resource
Comments
Medline ID
PubMed ID 11807269
Journal Acta Crystallogr D Biol Crystallogr
Year 2002
Volume 58
Pages 336-8
Authors Hirvonen M, Papageorgiou AC
Title Crystallization and preliminary crystallographic analysis of a family 45 endoglucanase from the thermophilic fungus Melanocarpus albomyces.
Related PDB
Related UniProtKB

Comments
This enzyme belongs to the glycosyl hydrolase family-45, with an inverting mechanism.
According to the literature [2], [4] & [5], Asp10 and Asp121 act as a general base and a general acid, respectively. According to the literature [4], the hydrolysis of glycosidic bond proceeds via a transition state with an oxocarbonium ion character, suggesting an SN1-like reaction, as follows:
(1) Asp121 acts as a general acid to protonate the glycosidic oxygen.
(2) Asp10 acts as a general base, which activates a solvent water molecule.
(3) The activated water makes a nucleophilic attack on the glycosidic carbon atom (C1 atom). This reaction occurs via a transition-state with an elongated glycosidic bond, suggesting an SN1-like (dissociative) mechanism.
(4) Finally, sugar product with an inverted configuration at C1 atom is formed.

Created Updated
2004-03-19 2009-03-17