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
 15377
 		17057
 17057
PubChem 22247451
 962
 22247451
 962
 		439178
 439178
1hd5A Unbound Unbound Unbound
2engA Unbound Unbound Unbound
3engA Unbound Unbound Bound:CBI
4engA 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 ASP 10;ASP 122
2engA ASP 10;ASP 121
3engA ASP 10;ASP 121
4engA ;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