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| <StructureSection load='' size='350' side='right' caption='E. coli transketolase 1 dimer complex with xylulose-5-phosphate-thiamine diphosphate adduct, ethylene glycol and Ca+2 ion (green) (PDB code [[2r8o]]).' scene='46/466534/Cv/1'> | | <StructureSection load='' size='350' side='right' caption='E. coli transketolase 1 dimer complex with xylulose-5-phosphate-thiamine diphosphate adduct, ethylene glycol and Ca+2 ion (green) (PDB code [[2r8o]]).' scene='46/466534/Cv/1'> |
| == Function == | | == Function == |
| '''Transketolase''' (TKT) catalyzes two opposite reactions. The synthesis of sedoheptulose-7-P in the pentose phosphate pathway using thiamine diphosphate (TPP) as co-factor; and the conversion of sedoheptulose-7-P and glyceraldehyde-3-P to aldose and ketose in the Calvin cycle<ref>PMID:8369276</ref>. Split-gene TKT is found in the hyperthermophilic bacterium ''Carboxydothermus hydrogenoformans'' and is reconstituted from 2 separate polypeptide chains<ref>PMID:33193259</ref>. | | '''Transketolase''' (TKT) catalyzes two opposite reactions. The synthesis of sedoheptulose-7-P in the pentose phosphate pathway using thiamine diphosphate (TPP) as co-factor; and the conversion of sedoheptulose-7-P and glyceraldehyde-3-P to aldose and ketose in the Calvin cycle<ref>PMID:8369276</ref>. '''Split-gene TKT''' is found in the hyperthermophilic bacterium ''Carboxydothermus hydrogenoformans'' and is reconstituted from 2 separate polypeptide chains<ref>PMID:33193259</ref>. |
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| == Structural highlights == | | == Structural highlights == |
Revision as of 09:45, 14 December 2020
| Function
Transketolase (TKT) catalyzes two opposite reactions. The synthesis of sedoheptulose-7-P in the pentose phosphate pathway using thiamine diphosphate (TPP) as co-factor; and the conversion of sedoheptulose-7-P and glyceraldehyde-3-P to aldose and ketose in the Calvin cycle[1]. Split-gene TKT is found in the hyperthermophilic bacterium Carboxydothermus hydrogenoformans and is reconstituted from 2 separate polypeptide chains[2].
Structural highlights
The active site of TKT contains a ligand-cofactor adduct.[3] Water molecules are shown as red spheres. Ca coordination site.
- ↑ Verschueren KH, Kingma J, Rozeboom HJ, Kalk KH, Janssen DB, Dijkstra BW. Crystallographic and fluorescence studies of the interaction of haloalkane dehalogenase with halide ions. Studies with halide compounds reveal a halide binding site in the active site. Biochemistry. 1993 Sep 7;32(35):9031-7. PMID:8369276
- ↑ James P, Isupov MN, De Rose SA, Sayer C, Cole IS, Littlechild JA. A 'Split-Gene' Transketolase From the Hyper-Thermophilic Bacterium Carboxydothermus hydrogenoformans: Structure and Biochemical Characterization. Front Microbiol. 2020 Oct 30;11:592353. doi: 10.3389/fmicb.2020.592353., eCollection 2020. PMID:33193259 doi:https://dx.doi.org/10.3389/fmicb.2020.592353
- ↑ Asztalos P, Parthier C, Golbik R, Kleinschmidt M, Hubner G, Weiss MS, Friedemann R, Wille G, Tittmann K. Strain and near attack conformers in enzymic thiamin catalysis: X-ray crystallographic snapshots of bacterial transketolase in covalent complex with donor ketoses xylulose 5-phosphate and fructose 6-phosphate, and in noncovalent complex with acceptor aldose ribose 5-phosphate. Biochemistry. 2007 Oct 30;46(43):12037-52. Epub 2007 Oct 3. PMID:17914867 doi:10.1021/bi700844m
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3D Structures of transketolase
Updated on 14-December-2020
{"openlevels":0}
- Transketolase
- 1trk – yTKT – yeast
- 1ay0 – yTKT (mutant)
- 2e6k – TKT – Thermus thermophilus
- 3hyl – BaTKT – Bacillus anthracis
- 3kom – TKT (mutant) – Francisella tularensis
- 3l84 – CjTKT – Campylobacter jejuni
- 3rim – TKT – Mycobacterium tuberculosis
- 3uk1 – BtTKT – Burkholderia thailandensis
- 4c7v - LsTKT – Lactobacillus salivarius
- 4xeu - TKT – Pseudomonas aeruginosa
- 5i4i, 5xry - PsTKT – Pichia stipitis
- 5hgx, 5i5g - PsTKT (mutant)
- 5nd6 - CrTKT – Chlamydomonas reinhardtii
- 5vrb - TKT – Neisseria gonorrhoeae
- 6rjc - EcTKT 1 – Escherichia coli
- Transketolase binary complexes
- 3mos, 3ooy – hTKT + TPP - human
- 4kxy - hTKT + TPP analog
- 6ha3 - hTKT (mutant) + fructose phosphate/TPP
- 6had, 6rjb - hTKT (mutant) + TDP
- 1itz - TKT + TPP – maize
- 1tka, 1tkb, 1tkc – yTKT + TPP analog
- 1gpu - yTKT 1 + TPP derivative
- 1qgd - EcTKT + TPP
- 6tj8 - EcTKT 1 + TPP analog
- 5hht - EcTKT (mutant) + TDP
- 1r9j - TKT + TPP – Leishmania mexicana
- 4c7x - LsTKT + TPP
- 5hyv, 5x56, 5xuf, 5xvt, 5xs6 - PsTKT + TPP
- 5xsa, 5xsb, 5xsm, 5xt0, 5xt4, 5xtv, 5xtx - PsTKT + TPP intermediate
- 5xqk - PsTKT + xylulose-5-P
- 5xqa - PsTKT + ribose-5-P
- 5xps - PsTKT + erythrose-4-P
- 5xrv - PsTKT + fructose-6-P
- 5i51 - PsTKT (mutant) + fructose-6-P
- 5xtl - PsTKT + pyrimidine derivative
- 5nd5 - CrTKT + TPP
- 3m49 – BaTKT + TPP
- Transketolase ternary complexes
- 4kxu - hTKT + TPP + sorbitol 6-P
- 4kxv, 4kxw - hTKT + TPP + xylitol 5-P
- 4kxx - hTKT + TPP + seduheptulose 7-P
- 1ngs - yTKT + TPP + Ca + erythrose-4-P
- 3m7i, 3m6l – CjTKT + TPP + ribose 5-P
- 3m34 - CjTKT + TPP + Ca
- 2r5n – EcTKT 1 + TPP + ribose 5-P
- 3upt,5xqa - BtTKT + TPP + ribose 5-P
- 2r8o, 5xqk - EcTKT 1 + TPP + xylulose 5-P
- 6tj9 - EcTKT 1 + TPP analog + xylulose 5-P
- 2r8p - EcTKT 1 + TPP + fructose 6-P
- 5hje - PsTKT + TPP + seduheptulose 7-P
- 5i51, 5xrv, 5xu2 - PsTKT + TPP + fructose 6-P
- 5xps, 5xu9 - PsTKT + TPP + erythrose 4-P
- 5i5e - PsTKT (mutant) + TPP + xylulose 5-P
- Split-gene transketolase
- 6yak - ChTKT N-terminal + C-terminal chain – Carboxydothermus hydrogenoformans
- 6yaj - ChTKT C-terminal chain
References
