EzCatDB: S00208

DB codeS00208
RLCP classification1.30.35885.972
CATH domainDomain 13.20.20.80Catalytic domain
E.C.3.2.1.58
CSA1cz1

CATH domainRelated DB codes (homologues)
3.20.20.80S00202,S00210,S00748,S00906,S00907,S00911,S00912,S00915,M00134,M00160,D00479,S00204,S00205,S00206,S00207,S00203,S00209,S00211,S00213,S00214,M00113,T00307,D00165,D00166,D00169,D00176,D00501,D00502,D00503,D00844,D00861,D00864,M00026,M00112,M00193,M00346,T00057,T00062,T00063,T00066,T00067

Enzyme Name
Swiss-protKEGG

P29717
Protein nameGlucan 1,3-beta-glucosidaseglucan 1,3-beta-glucosidase
exo-1,3-beta-glucosidase
beta-1,3-glucan exo-hydrolase
exo (1->3)-glucanohydrolase
1,3-beta-glucan glucohydrolase
SynonymsEC 3.2.1.58
Exo-1,3-beta-glucanase

KEGG pathways
MAP codePathways
MAP00500Starch and sucrose metabolism

Swiss-prot:Accession NumberP29717
Entry nameEXG_CANAL
ActivitySuccessive hydrolysis of beta-D-glucose units from the non-reducing ends of (1->3)-beta-D-glucans, releasing alpha-glucose.
SubunitMonomer.
Subcellular locationSecreted.
Cofactor


SubstratesProductsintermediates
KEGG-idC00965C00001C02048C00965C00267I00119
Compound1,3-beta-D-GlucanH2OLaminaribiose1,3-beta-D-Glucanalpha-D-GlucosePeptidyl-Glu-1,3-beta-D-glucanTransition state in deglycosylation
TypepolysaccharideH2Opolysaccharidepolysaccharidecarbohydrate

1cz1AUnbound
UnboundUnboundUnboundUnboundUnbound
1eqcAUnbound
UnboundUnboundUnboundUnboundTransition-state-analogue:CTS
1eqpAUnbound
UnboundUnboundUnboundUnboundUnbound

Active-site residues
resource
Swiss-prot;P29717 (see [Comments])
pdbCatalytic residues
1cz1AARG 92;ASN 191;GLU 192;HIS 253;TYR 255;GLU 292
1eqcAARG 92;ASN 191;GLU 192;HIS 253;TYR 255;GLU 292
1eqpAARG 92;ASN 191;GLU 192;HIS 253;TYR 255;GLU 292

References for Catalytic Mechanism
ReferencesSectionsNo. of steps in catalysis
[2]Scheme 14
[3]Fig.2, p.648-6494
[4]Fig.1, p.779-780

references
[1]
Commentscrystallization, diffraction (1.9 angstroms)
PubMed ID1583691
JournalJ Mol Biol
Year1992
Volume225
Pages217-8
AuthorsCutfield S, Brooke G, Sullivan P, Cutfield J
TitleCrystallization of the exo(1,3)-beta-glucanase from Candida albicans.
[2]
CommentsActive site glu-330.
Medline ID97166150
PubMed ID9013549
JournalJ Biol Chem
Year1997
Volume272
Pages3161-7
AuthorsMacKenzie LF, Brooke GS, Cutfield JF, Sullivan PA, Withers SG
TitleIdentification of Glu-330 as the catalytic nucleophile of Candida albicans exo-beta-(1,3)-glucanase.
Related Swiss-protP29717
[3]
CommentsReview
PubMed ID9345622
JournalCurr Opin Struct Biol
Year1997
Volume7
Pages645-51
AuthorsWhite A, Rose DR
TitleMechanism of catalysis by retaining beta-glycosyl hydrolases.
[4]
CommentsX-ray crystallography (1.85 angstroms) of 45-438.
Medline ID20079533
PubMed ID10610795
JournalJ Mol Biol
Year1999
Volume294
Pages771-83
AuthorsCutfield SM, Davies GJ, Murshudov G, Anderson BF, Moody PC, Sullivan PA, Cutfield JF
TitleThe structure of the exo-beta-(1,3)-glucanase from Candida albicans in native and bound forms: relationship between a pocket and groove in family 5 glycosyl hydrolases.
Related PDB1cz1,1eqc
Related Swiss-protP29717
[5]
Commentscrystal structure
PubMed ID11112513
JournalProtein Eng
Year2000
Volume13
Pages735-8
AuthorsCutfield JF, Sullivan PA, Cutfield SM
TitleMinor Structural Consequences of the Alternative Cug Codon Usage (Ser for Leu) in Candida Albicans Exoglucanase.
Related PDB1eqp

comments
This enzyme belongs to the glycosidase family-5.
The paper [3] described general aspects of the catalytic mechanism of retaining beta-glycosyl hydrolases. Accoriding to the paper, the mechanism can be described as follows:
(1) Saccharide binds in a "twisted-boat" conformation.
(2) The beta-1,4 linkage is broken, leading to the formation of a transition state with a slight positive charge at the anomeric carbon, in a "half-chair" conformation, which develops a oxocarbenium-ion-like character.
(3) An approach of the ionic species to the catalytic nucleophile leads to the formation of a covalent intermediate of inverted alpha-configuration in a so-called chair conformation. The aglycon is released and a water molecule diffuses into the vicinity of the acidic residue as a general base.
(4) The covalent intermediate reactivates through an oxocarbenium-ion-like transition state. The general base abstracts a proton from the incoming water, which in turn carries out a nucleophilic attack on the C1 atom of the residual saccharide.
Moreover, comparing the structural data with that of xylanase (E.C. 3.2.1.8) (D00479 in EzCatDB) and the other family-5 enzyme, cellulase (E.C. 3.2.1.4) (S00203 in EzCatDB), Tyr255 might stabilize the leaving nucleophile, Glu292 in deglycosylation, whilst His253 might modulate the activity of Glu192. On the other hand, Tyr255 might modulate the activity of the nucleophile, according to the data of the other homologous enzyme, beta-glucosidase (E.C. 3.2.1.21) (S00205 in EzCatDB).

createdupdated
2003-02-032012-02-14


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 2010)
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)

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