DB code: S00198

RLCP classification 6.10.400000.116 : Double-bonded atom exchange
5.121.670200.6100 : Elimination
4.121.143000.6100 : Addition
6.20.7100.6120 : Double-bonded atom exchange
CATH domain 3.20.20.70 : TIM Barrel Catalytic domain
E.C. 2.2.1.2
CSA 1onr
M-CSA 1onr
MACiE M0148

CATH domain Related DB codes (homologues)
3.20.20.70 : TIM Barrel S00215 S00217 S00218 S00219 S00532 S00220 S00745 S00537 S00538 S00539 S00826 S00841 S00235 S00239 S00240 S00243 S00244 S00199 S00200 S00201 S00221 S00222 S00847 S00224 S00225 S00226 D00014 D00029 M00141 T00015 T00239 D00664 D00665 D00804 D00863 T00089

Uniprot Enzyme Name
UniprotKB Protein name Synonyms RefSeq Pfam
P0A870 Transaldolase B
EC 2.2.1.2
NP_414549.1 (Protein)
NC_000913.2 (DNA/RNA sequence)
YP_488314.1 (Protein)
NC_007779.1 (DNA/RNA sequence)
PF00923 (Transaldolase)
[Graphical View]
P37837 Transaldolase
EC 2.2.1.2
NP_006746.1 (Protein)
NM_006755.1 (DNA/RNA sequence)
PF00923 (Transaldolase)
[Graphical View]

KEGG enzyme name
transaldolase
dihydroxyacetonetransferase
dihydroxyacetone synthase
formaldehyde transketolase

UniprotKB: Accession Number Entry name Activity Subunit Subcellular location Cofactor
P0A870 TALB_ECOLI Sedoheptulose 7-phosphate + D-glyceraldehyde 3-phosphate = D-erythrose 4-phosphate + D-fructose 6-phosphate. Homodimer. Cytoplasm (Probable).
P37837 TALDO_HUMAN Sedoheptulose 7-phosphate + D-glyceraldehyde 3-phosphate = D-erythrose 4-phosphate + D-fructose 6-phosphate. Cytoplasm (Probable).

KEGG Pathways
Map code Pathways E.C.
MAP00030 Pentose phosphate pathway

Compound table
Substrates Products Intermediates
KEGG-id C00085 C00279 C00118 C00281
E.C. (1st intermediate)
Compound D-Fructose 6-phosphate D-Erythrose 4-phosphate D-Glyceraldehyde 3-phosphate Sedoheptulose 7-phosphate Schiff-base intermediate
Type carbohydrate,phosphate group/phosphate ion carbohydrate,phosphate group/phosphate ion carbohydrate,phosphate group/phosphate ion carbohydrate,phosphate group/phosphate ion
ChEBI 61553
48153
29052
PubChem 439160
122357
439168
1f05A Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1f05B Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1i2nA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1i2nB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1i2oA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1i2oB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1i2pA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1i2pB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1i2qA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1i2qB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1i2rA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1i2rB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1onrA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1onrB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1ucwA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Intermediate-analogue:LLY
1ucwB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Intermediate-analogue:LLY

Reference for Active-site residues
resource references E.C.
Swiss-prot;P30148, P37837 & literature [7], [9], [10], [12], [17]

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
1f05A Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 27;GLU 106;LYS 142;THR 167
1f05B Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 27;GLU 106;LYS 142;THR 167
1i2nA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 17;GLU 96;LYS 132;THR 156 mutant N35A
1i2nB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 17;GLU 96;LYS 132;THR 156 mutant N35A
1i2oA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 17; ;LYS 132;THR 156 mutant E96A
1i2oB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 17; ;LYS 132;THR 156 mutant E96A
1i2pA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ;GLU 96;LYS 132;THR 156 mutant D17A
1i2pB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ;GLU 96;LYS 132;THR 156 mutant D17A
1i2qA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 17;GLU 96;LYS 132; mutant T156A
1i2qB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 17;GLU 96;LYS 132; mutant T156A
1i2rA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 17;GLU 96;LYS 132;THR 156 mutant S176A
1i2rB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 17;GLU 96;LYS 132;THR 156 mutant S176A
1onrA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 17;GLU 96;LYS 132;THR 156
1onrB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 17;GLU 96;LYS 132;THR 156
1ucwA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 17;GLU 96;LLY 132;THR 156 LLY 132(modified with reduced schiff-base intermediate)
1ucwB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ASP 17;GLU 96;LLY 132;THR 156 LLY 132(modified with reduced schiff-base intermediate)

References for Catalytic Mechanism
References Sections No. of steps in catalysis
[10]
Fig.5, p.721
[11]
p.305
[12]
Fig.5, p.122
[14]
p.294-295
[17]
Fig.4, p.2412-2414

References
[1]
Resource
Comments
Medline ID
PubMed ID 4799825
Journal Biochemistry
Year 1973
Volume 12
Pages 5217-23
Authors Kuhn E, Brand K
Title Computer analysis of the two-substrate reaction catalyzed by yeast and bovine transaldolase
Related PDB
Related UniProtKB
[2]
Resource
Comments
Medline ID
PubMed ID 945040
Journal Arch Biochem Biophys
Year 1976
Volume 173
Pages 577-85
Authors Tsolas O, Horecker BL
Title Half-of-the-sites activity of transaldolase
Related PDB
Related UniProtKB
[3]
Resource
Comments
Medline ID
PubMed ID 776982
Journal J Biol Chem
Year 1976
Volume 251
Pages 4220-3
Authors Christen P, Gasser A
Title Oxidation of the carbanion intermediate of transaldolase by hexacyanoferrate (III)
Related PDB
Related UniProtKB
[4]
Resource
Comments
Medline ID
PubMed ID 728110
Journal Biochem J
Year 1978
Volume 176
Pages 257-82
Authors Williams JF, Blackmore PF, Clark MG
Title New reaction sequences for the non-oxidative pentose phosphate pathway
Related PDB
Related UniProtKB
[5]
Resource
Comments
Medline ID
PubMed ID 8357848
Journal Biochim Biophys Acta
Year 1993
Volume 1182
Pages 162-78
Authors Schrader MC, Eskey CJ, Simplaceanu V, Ho C
Title A carbon-13 nuclear magnetic resonance investigation of the metabolic fluxes associated with glucose metabolism in human erythrocytes
Related PDB
Related UniProtKB
[6]
Resource
Comments
Medline ID
PubMed ID 8477719
Journal Eur J Biochem
Year 1993
Volume 213
Pages 477-85
Authors Flanigan I, Collins JG, Arora KK, MacLeod JK, Williams JF
Title Exchange reactions catalyzed by group-transferring enzymes oppose the quantitation and the unravelling of the identify of the pentose pathway
Related PDB
Related UniProtKB
[7]
Resource
Comments
Medline ID
PubMed ID 8109173
Journal Yeast
Year 1993
Volume 9
Pages 1241-9
Authors Miosga T, Schaaff-Gerstenschlager I, Franken E, Zimmermann FK
Title Lysine144 is essential for the catalytic activity of Saccharomyces cerevisiae transaldolase
Related PDB
Related UniProtKB
[8]
Resource
Comments
Medline ID
PubMed ID 8534086
Journal Appl Environ Microbiol
Year 1995
Volume 61
Pages 4184-90
Authors Walfridsson M, Hallborn J, Penttila M, Keranen S, Hahn-Hagerdal B
Title Xylose-metabolizing Saccharomyces cerevisiae strains overexpressing the TKL1 and TAL1 genes encoding the pentose phosphate pathway enzymes transketolase and transaldolase
Related PDB
Related UniProtKB
[9]
Resource
Comments
Medline ID
PubMed ID 8549825
Journal FEBS Lett
Year 1996
Volume 378
Pages 161-5
Authors Banki K, Perl A
Title Inhibition of the catalytic activity of human transaldolase by antibodies and site-directed mutagenesis
Related PDB
Related UniProtKB
[10]
Resource
Comments X-RAY CRYSTALLOGRAPHY (1.87 ANGSTROMS).
Medline ID 96399717
PubMed ID 8805555
Journal Structure
Year 1996
Volume 4
Pages 715-24
Authors Jia J, Huang W, Schorken U, Sahm H, Sprenger GA, Lindqvist Y, Schneider G
Title Crystal structure of transaldolase B from Escherichia coli suggests a circular permutation of the alpha/beta barrel within the class I aldolase family
Related PDB 1onr
Related UniProtKB P30148
[11]
Resource
Comments
Medline ID
PubMed ID 9343352
Journal Annu Rev Microbiol
Year 1997
Volume 51
Pages 285-310
Authors Takayama S, McGarvey GJ, Wong CH
Title Microbial aldolases and transketolases
Related PDB
Related UniProtKB
[12]
Resource
Comments X-RAY CRYSTALLOGRAPHY (2.2 ANGSTROMS).
Medline ID 97160483
PubMed ID 9007983
Journal Protein Sci
Year 1997
Volume 6
Pages 119-24
Authors Jia J, Schorken U, Lindqvist Y, Sprenger GA, Schneider G
Title Crystal structure of the reduced Schiff-base intermediate complex of transaldolase B from Escherichia coli
Related PDB 1ucw
Related UniProtKB P30148
[13]
Resource
Comments
Medline ID
PubMed ID 9883893
Journal FEBS Lett
Year 1998
Volume 441
Pages 247-50
Authors Schorken U, Jia J, Sahm H, Sprenger GA, Schneider G
Title Disruption of Escherichia coli transaldolase into catalytically active monomers
Related PDB
Related UniProtKB
[14]
Resource
Comments
Medline ID
PubMed ID 10048322
Journal Protein Sci
Year 1999
Volume 8
Pages 291-7
Authors Dalby A, Dauter Z, Littlechild JA
Title Crystal structure of human muscle aldolase complexed with fructose 1,6-bisphosphate
Related PDB
Related UniProtKB
[15]
Resource
Comments X-ray crystallography
Medline ID
PubMed ID 10869557
Journal FEBS Lett
Year 2000
Volume 475
Pages 205-8
Authors Thorell S, Gergely P Jr, Banki K, Perl A, Schneider G
Title The three-dimensional structure of human transaldolase
Related PDB 1f05
Related UniProtKB
[16]
Resource
Comments
Medline ID
PubMed ID 11705376
Journal Biochemistry
Year 2001
Volume 40
Pages 13868-75
Authors Choi KH, Shi J, Hopkins CE, Tolan DR, Allen KN
Title Snapshots of catalysis
Related PDB
Related UniProtKB
[17]
Resource
Comments X-RAY CRYSTALLOGRAPHY (2.05 ANGSTROMS).
Medline ID 21195256
PubMed ID 11298760
Journal Eur J Biochem
Year 2001
Volume 268
Pages 2408-15
Authors Schorken U, Thorell S, Schurmann M, Jia J, Sprenger GA, Schneider G
Title Identification of catalytically important residues in the active site of Escherichia coli transaldolase
Related PDB 1i2n 1i2o 1i2p 1i2q 1i2r
Related UniProtKB P30148
[18]
Resource
Comments
Medline ID
PubMed ID 11120740
Journal J Biol Chem
Year 2001
Volume 276
Pages 11055-61
Authors Schurmann M, Sprenger GA
Title Fructose-6-phosphate aldolase is a novel class I aldolase from Escherichia coli and is related to a novel group of bacterial transaldolases
Related PDB
Related UniProtKB
[19]
Resource
Comments
Medline ID
PubMed ID 12418227
Journal Methods Enzymol
Year 2002
Volume 354
Pages 197-201
Authors Schneider G, Sprenger GA
Title Transaldolase B: trapping of Schiff base intermediate between dihydroxyacetone and epsilon-amino group of active-site lysine residue by borohydride reduction.
Related PDB
Related UniProtKB

Comments
According to the literature [10], [12] & [17], the catalytic reactions of this enzyme proceed as follows:
(A) Exchange of double-bonded atoms; Schiff-base formation:
(A1) Glu96 (PDB;1onr) acts as a general base to abstract a proton from the sidechain of Lys132 through a water, enhancing its nucleophilicity. This water is oriented by Thr156.
(A2) The activated Lys132 makes a nucleophilic attack on C2-carbonyl carbon, to form a carbinolamine intermediate. The negative charge developed on the C2-oxygen of the intermediate is stabilized by interaction with Thr156. (Here, a proton must transfer from the sidechain amine of Lys132 to the C2-carbonyl oxygen, with a probable assistance by the same water. The water may protonate the C2-carbonyl oxygen, and then deprotonate the amine of Lys132.)
(A3) The lone pair of Lys132 makes another attak on C2-carbon, whilst Glu96 acts as a general acid to protonate the leaving hydroxyl group through the same water. This reaction leads to Schiff-base intermeidate formation.
(B) Eliminative double-bond formation;C3-C4 bond cleavage:
(B1) Glu17 acts as a general base to deprotonate C4-hydroxyl group, leading to the C3-C4 bond cleavage (E2-like reaction). This reaction leads to the formation of carbanion at C2 atom, and the release of the first product, G3P.
(B2) The negative charge formed at C2 facilitates the formation of C2=C3 double-bond, or ketamine (or enamine) intermediate.
(C) Additive double-bond deformation; Addition of the second substrate (E4P):
(C1) The C3 atom of the enamine intemediate makes a nucleophilic attack on the carbonyl carbon of the second substrate, E4P.
(C2) Asp17 acts as a general acid to protonate the aldehyde oxygen of E4P, facilitating the nucleophilic attack of the enamine on E4P. This reaction leads to the Schiff base at Lys132 again.
(D) Exchange of double-bonded atoms; Schiff-base deformation:
(D1) A water molecule is activated by a general base, Glu96, through a second water.
(D2) The activated water makes a nucleophilic attack on the Schiff base carbon, to form a carbinolamine intermediate. The negative charge developed on the C2-oxygen of the intermediate is stabilized by interaction with Thr156. (Here, a proton must transfer from the C2-hydroxylg group to the sidechain amine of Lys132, with a probable assistance by the same water. The water may deprotonate the C2-hydroxyl oxygen, and then protonate the amine of Lys132.)
(D3) The lone pair of the C2-oxygen makes a nucleophilic attack on the C2 atom, whilst Glu96 acts as a general acid to protonate the leaving Lys132 amine group through the same water. This reaction leads to release of the product.

Created Updated
2005-03-25 2009-03-11