DB code: S00194

RLCP classification 1.30.300.2 : Hydrolysis
CATH domain 3.20.20.40 : TIM Barrel Catalytic domain
E.C. 3.2.1.4
CSA
M-CSA
MACiE

CATH domain Related DB codes (homologues)
3.20.20.40 : TIM Barrel D00537 D00536

Uniprot Enzyme Name
UniprotKB Protein name Synonyms CAZy Pfam
Q7SIG5 Endoglucanase-6B
EC 3.2.1.4
Endo-1,4-beta-glucanase 6B
Cellulase 6B
GH6 (Glycoside Hydrolase Family 6)
PF01341 (Glyco_hydro_6)
[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
Q7SIG5 GUN6_HUMIN Endohydrolysis of (1->4)-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans. Monomer.

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

Compound table
Substrates Products Intermediates
KEGG-id C00760 C00001 C00478 C00551 C00760 C00551
E.C.
Compound Cellulose H2O Lichenin beta-D-Glucan Cellulose beta-D-Glucan
Type polysaccharide H2O carbohydrate polysaccharide polysaccharide polysaccharide
ChEBI 15377
 15377
PubChem 22247451
 962
 22247451
 962
 		439241
 439241
 		46173706
 46173706
 		46173706
 46173706
1dysA Unbound Unbound Unbound Unbound Unbound
1dysB Unbound Unbound Unbound Unbound Unbound

Reference for Active-site residues
resource references E.C.
see D00536

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
1dysA ASP 92;ASP 139;ASP 180;ASP 316
1dysB ASP 92;ASP 139;ASP 180;ASP 316

References for Catalytic Mechanism
References Sections No. of steps in catalysis
[10]
p.9750-9751
[11]
p.204-206

References
[1]
Resource
Comments
Medline ID
PubMed ID 8215374
Journal Appl Environ Microbiol
Year 1993
Volume 59
Pages 3032-43
Authors Jung ED, Lao G, Irwin D, Barr BK, Benjamin A, Wilson DB
Title DNA sequences and expression in Streptomyces lividans of an exoglucanase gene and an endoglucanase gene from Thermomonospora fusca.
Related PDB
Related UniProtKB
[2]
Resource
Comments X-RAY CRYSTALLOGRAPHY (1.8 ANGSTROMS) OF 32-317.
Medline ID 94002001
PubMed ID 8399160
Journal Biochemistry
Year 1993
Volume 32
Pages 9906-16
Authors Spezio M, Wilson DB, Karplus PA
Title Crystal structure of the catalytic domain of a thermophilic endocellulase.
Related PDB 1tml
Related UniProtKB P26222
[3]
Resource
Comments
Medline ID
PubMed ID 7789807
Journal Gene
Year 1995
Volume 158
Pages 23-9
Authors Quillet L, Barray S, Labedan B, Petit F, Guespin-Michel J
Title The gene encoding the beta-1,4-endoglucanase (CelA) from Myxococcus xanthus: evidence for independent acquisition by horizontal transfer of binding and catalytic domains from actinomycetes.
Related PDB
Related UniProtKB
[4]
Resource
Comments
Medline ID
PubMed ID 8615816
Journal Biochem J
Year 1996
Volume 315
Pages 467-72
Authors Damude HG, Ferro V, Withers SG, Warren RA
Title Substrate specificity of endoglucanase A from Cellulomonas fimi: fundamental differences between endoglucanases and exoglucanases from family 6.
Related PDB
Related UniProtKB
[5]
Resource
Comments
Medline ID
PubMed ID 8824619
Journal J Bacteriol
Year 1996
Volume 178
Pages 5732-40
Authors Ahsan MM, Kimura T, Karita S, Sakka K, Ohmiya K
Title Cloning, DNA sequencing, and expression of the gene encoding Clostridium thermocellum cellulase CelJ, the largest catalytic component of the cellulosome.
Related PDB
Related UniProtKB
[6]
Resource
Comments
Medline ID
PubMed ID 9438981
Journal Biosci Biotechnol Biochem
Year 1997
Volume 61
Pages 2004-9
Authors Hitomi J, Hatada Y, Kawaminami S, Kawai S, Ito S
Title Amino acid sequence and stereoselective hydrolytic reaction of an endo-1,4-beta-glucanase from a Bacillus strain.
Related PDB
Related UniProtKB
[7]
Resource
Comments
Medline ID
PubMed ID 9335169
Journal J Biotechnol
Year 1997
Volume 57
Pages 101-13
Authors Zhang S, Wilson DB
Title Surface residue mutations which change the substrate specificity of Thermomonospora fusca endoglucanase E2.
Related PDB
Related UniProtKB
[8]
Resource
Comments
Medline ID
PubMed ID 9649302
Journal Biochemistry
Year 1998
Volume 37
Pages 9220-9
Authors Barr BK, Wolfgang DE, Piens K, Claeyssens M, Wilson DB
Title Active-site binding of glycosides by Thermomonospora fusca endocellulase E2.
Related PDB
Related UniProtKB
[9]
Resource
Comments
Medline ID
PubMed ID 10029552
Journal Biochemistry
Year 1999
Volume 38
Pages 2570-6
Authors Beadle BM, Baase WA, Wilson DB, Gilkes NR, Shoichet BK
Title Comparing the thermodynamic stabilities of a related thermophilic and mesophilic enzyme.
Related PDB
Related UniProtKB
[10]
Resource
Comments
Medline ID
PubMed ID 10423254
Journal Biochemistry
Year 1999
Volume 38
Pages 9746-51
Authors Wolfgang DE, Wilson DB
Title Mechanistic studies of active site mutants of Thermomonospora fusca endocellulase E2.
Related PDB
Related UniProtKB
[11]
Resource
Comments X-ray crystallography
Medline ID
PubMed ID 10794732
Journal Biochem J
Year 2000
Volume 348 Pt 1
Pages 201-7
Authors Davies GJ, Brzozowski AM, Dauter M, Varrot A, Schulein M
Title Structure and function of Humicola insolens family 6 cellulases: structure of the endoglucanase, Cel6B, at 1.6 A resolution.
Related PDB 1dys
Related UniProtKB
[12]
Resource
Comments
Medline ID
PubMed ID 10731432
Journal J Mol Biol
Year 2000
Volume 297
Pages 819-28
Authors Varrot A, Schulein M, Davies GJ
Title Insights into ligand-induced conformational change in Cel5A from Bacillus agaradhaerens revealed by a catalytically active crystal form.
Related PDB
Related UniProtKB
[13]
Resource
Comments
Medline ID
PubMed ID 11311718
Journal Int J Biol Macromol
Year 2001
Volume 28
Pages 285-92
Authors Novo C, Simoes F, Mendonca D, Matos J, Clemente A
Title Primary structure deduction and molecular modelling from a cDNA of a cellobiohydrolase-like protein from the white-rot fungus Coriolus versicolor.
Related PDB
Related UniProtKB
[14]
Resource
Comments
Medline ID
PubMed ID 11514516
Journal J Bacteriol
Year 2001
Volume 183
Pages 5325-33
Authors Steenbakkers PJ, Li XL, Ximenes EA, Arts JG, Chen H, Ljungdahl LG, Op Den Camp HJ
Title Noncatalytic docking domains of cellulosomes of anaerobic fungi.
Related PDB
Related UniProtKB
[15]
Resource
Comments
Medline ID
PubMed ID 11495244
Journal J Biomol NMR
Year 2001
Volume 20
Pages 127-33
Authors Permi P, Annila A
Title A new approach for obtaining sequential assignment of large proteins.
Related PDB
Related UniProtKB
[16]
Resource
Comments
Medline ID
PubMed ID 12071852
Journal Biochem J
Year 2002
Volume 365
Pages 193-204
Authors Steenbakkers PJ, Ubhayasekera W, Goossen HJ, van Lierop EM, van der Drift C, Vogels GD, Mowbray SL, Op den Camp HJ
Title An intron-containing glycoside hydrolase family 9 cellulase gene encodes the dominant 90 kDa component of the cellulosome of the anaerobic fungus Piromyces sp. strain E2.
Related PDB
Related UniProtKB

Comments
This enzyme is homologous to the catalytic domain of the counterpart enzyme from Thermomonospora fusca (D00536 in EzCatDB).
This family belongs to Glycosidase family-6, which has an inverting mechanism (equatorial to axial conformation). Furthermore, this enzyme belongs to endoglucanase, whilst its family member (EC 3.2.1.91) is exoglucanase.
According to the Swiss-prot (P26222), Asp139 (1dys) acts as proton donor, whilst Asp316 acts as base. The rest of aspartic residues serve as pKa modulator. However, literature [10] suggests that the residue corresponding to Asp316 plays an important role in binding rather than as base. In contrast, [11] suggests that the possiblity of Asp316 as base catalyst could not be ruled out.

Created Updated
2002-10-15 2009-03-24