DB code: S00202

RLCP classification 3.900.275800.990 : Transfer
CATH domain 3.20.20.80 : TIM Barrel Catalytic domain
E.C. 2.4.1.25
CSA 1cwy
M-CSA 1cwy
MACiE

CATH domain Related DB codes (homologues)
3.20.20.80 : TIM Barrel S00210 S00748 S00906 S00907 S00911 S00912 S00915 M00134 M00160 D00479 S00204 S00205 S00206 S00207 S00203 S00208 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

Uniprot Enzyme Name
UniprotKB Protein name Synonyms CAZy Pfam
O87172 4-alpha-glucanotransferase
EC 2.4.1.25
Amylomaltase
Disproportionating enzyme
D-enzyme
GH77 (Glycoside Hydrolase Family 77)
PF02446 (Glyco_hydro_77)
[Graphical View]

KEGG enzyme name
4-alpha-glucanotransferase
disproportionating enzyme
dextrin glycosyltransferase
D-enzyme
debranching enzyme maltodextrin glycosyltransferase
amylomaltase
dextrin transglycosylase
1,4-alpha-D-glucan:1,4-alpha-D-glucan 4-alpha-D-glycosyltransferase

UniprotKB: Accession Number Entry name Activity Subunit Subcellular location Cofactor
O87172 MALQ_THETH Transfers a segment of a (1->4)-alpha-D-glucan to a new position in an acceptor, which may be glucose or a (1->4)-alpha-D-glucan. Cytoplasm (By similarity).

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

Compound table
Substrates Products Intermediates
KEGG-id C00718 C00293 C00208
E.C.
Compound Amylose Glucose Maltose
Type polysaccharide carbohydrate polysaccharide
ChEBI 17306
PubChem 439186
1cwyA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
1eswA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Analogue:ACR_651 Unbound Unbound
1fp8A Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
1fp9A Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound

Reference for Active-site residues
resource references E.C.
literature [11]

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
1cwyA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 293;GLU 340;HIS 394;ASP 395
1eswA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 293;GLU 340;HIS 394;ASP 395
1fp8A Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 293;GLU 340;HIS 394;ASP 395
1fp9A Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 293;GLU 340;HIS 394;ASP 395

References for Catalytic Mechanism
References Sections No. of steps in catalysis
[7]
p.1057
[10]
p.6910-6911
[11]
Fig.1, p.879-882

References
[1]
Resource
Comments
Medline ID
PubMed ID 2086786
Journal J Protozool
Year 1990
Volume 37
Pages 576-80
Authors Werries E, Franz A, Geisemeyer S
Title Detection of glycogen-debranching system in trophozoites of Entamoeba histolytica
Related PDB
Related UniProtKB
[2]
Resource
Comments
Medline ID
PubMed ID 7678257
Journal J Biol Chem
Year 1993
Volume 268
Pages 1391-6
Authors Takaha T, Yanase M, Okada S, Smith SM
Title Disproportionating enzyme (4-alpha-glucanotransferase; EC 2.4.1.25) of potato. Purification, molecular cloning, and potential role in starch metabolism
Related PDB
Related UniProtKB
[3]
Resource
Comments
Medline ID
PubMed ID 85430201
Journal FEBS Lett
Year 1995
Volume 377
Pages 6-8
Authors Janecek S
Title Close evolutionary relatedness among functionally distantly related members of the (alpha/beta)8-barrel glycosyl hydrolases suggested by the similarity of their fifth conserved sequence region
Related PDB
Related UniProtKB
[4]
Resource
Comments
Medline ID
PubMed ID 8621678
Journal J Biol Chem
Year 1996
Volume 271
Pages 2902-8
Authors Takaha T, Yanase M, Takata H, Okada S, Smith SM
Title Potato D-enzyme catalyzes the cyclization of amylose to produce cycloamylose, a novel cyclic glucan
Related PDB
Related UniProtKB
[5]
Resource
Comments
Medline ID
PubMed ID 9353929
Journal Microbiology
Year 1997
Volume 143
Pages 3287-94
Authors Goda SK, Eissa O, Akhtar M, Minton NP
Title Molecular analysis of a Clostridium butyricum NCIMB 7423 gene encoding 4-alpha-glucanotransferase and characterization of the recombinant enzyme produced in Escherichia coli
Related PDB
Related UniProtKB
[6]
Resource
Comments
Medline ID
PubMed ID 9642157
Journal Biochem Biophys Res Commun
Year 1998
Volume 247
Pages 493-7
Authors Takaha T, Yanase M, Takata H, Okada S, Smith SM
Title Cyclic glucans produced by the intramolecular transglycosylation activity of potato D-enzyme on amylopectin
Related PDB
Related UniProtKB
[7]
Resource
Comments
Medline ID
PubMed ID 9990324
Journal Eur J Biochem
Year 1998
Volume 258
Pages 1050-8
Authors Meissner H, Liebl W
Title Thermotoga maritima maltosyltransferase, a novel type of maltodextrin glycosyltransferase acting on starch and malto-oligosaccharides
Related PDB
Related UniProtKB
[8]
Resource
Comments
Medline ID
PubMed ID 10049841
Journal Appl Environ Microbiol
Year 1999
Volume 65
Pages 910-5
Authors Terada Y, Fujii K, Takaha T, Okada S
Title Thermus aquaticus ATCC 33923 amylomaltase gene cloning and expression and enzyme characterization
Related PDB
Related UniProtKB
[9]
Resource
Comments
Medline ID
PubMed ID 10380338
Journal Biopolymers
Year 1999
Volume 50
Pages 145-51
Authors Nakatani H
Title Monte Carlo simulation of 4-alpha-glucanotransferase reaction
Related PDB
Related UniProtKB
[10]
Resource
Comments X-ray crystallography
Medline ID
PubMed ID 11082203
Journal Eur J Biochem
Year 2000
Volume 267
Pages 6903-13
Authors Przylas I, Terada Y, Fujii K, Takaha T, Saenger W, Strater N
Title X-ray structure of acarbose bound to amylomaltase from Thermus aquaticus. Implications for the synthesis of large cyclic glucans
Related PDB 1esw
Related UniProtKB
[11]
Resource
Comments X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS).
Medline ID 20143895
PubMed ID 10677288
Journal J Mol Biol
Year 2000
Volume 296
Pages 873-86
Authors Przylas I, Tomoo K, Terada Y, Takaha T, Fujii K, Saenger W, Strater N
Title Crystal structure of amylomaltase from thermus aquaticus, a glycosyltransferase catalysing the production of large cyclic glucans
Related PDB 1cwy
Related UniProtKB O87172

Comments
This enzyme is homologous to glycosidase family-13, to which alpha-amylase belongs. This family has a retaining mechanism.
These structures would be a part of Glycogen Debranching Enzyme System that has both of 4-alpha-glucanotransferase (EC 2.4.1.25) and amylo-1,6-glucosidase (EC 3.2.1.33) activities.
This enzyme can catalyze the cyclization of amylose, with intramolecular transfer reaction. The reaction proceeds as follows (see [11]):
(1) Glu340 acts as a general acid to protonate the glycosidic oxygen atom of the scissile bond, forming a oxocarbenium-like transition state. Here, Asp395 and His394 probably stabilize the transition state. (SN1-like reaction)
(2) Asp293 acts as a nucleophile to make an attack on the C1 atom of the substrate, forming the covalent intermediate.
(3) Glu340 now acts as a general base, to deprotonate the acceptor group, hydroxyl group.
(4) The activated acceptor group makes another nucleophilic attack on the C1 atom, to form a new covalent bond.

Created Updated
2004-03-22 2011-11-30