TKT_GEOSE
ID TKT_GEOSE Reviewed; 668 AA.
AC A0A0I9QGZ2;
DT 13-APR-2016, integrated into UniProtKB/Swiss-Prot.
DT 14-OCT-2015, sequence version 1.
DT 03-AUG-2022, entry version 21.
DE RecName: Full=Transketolase {ECO:0000303|Ref.2};
DE Short=TK {ECO:0000303|Ref.2};
DE EC=2.2.1.1 {ECO:0000305|Ref.2};
GN Name=tkt {ECO:0000312|EMBL:CTQ31223.1};
OS Geobacillus stearothermophilus (Bacillus stearothermophilus).
OC Bacteria; Firmicutes; Bacilli; Bacillales; Bacillaceae; Geobacillus.
OX NCBI_TaxID=1422;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=DSM 13240;
RA De Berardinis V.;
RL Submitted (JUN-2015) to the EMBL/GenBank/DDBJ databases.
RN [2]
RP FUNCTION, CATALYTIC ACTIVITY, SUBSTRATE SPECIFICITY, COFACTOR,
RP BIOPHYSICOCHEMICAL PROPERTIES, AND BIOTECHNOLOGY.
RC STRAIN=DSM 13240;
RX DOI=10.1002/adsc.201200590;
RA Abdoul-Zabar J., Sorel I., Helaine V., Charmantray F., Devamani T., Yi D.,
RA De Berardinis V., Louis D., Marliere P., Fessner W.-D., Hecquet L.;
RT "Thermostable transketolase from Geobacillus stearothermophilus:
RT characterization and catalytic properties.";
RL Adv. Synth. Catal. 355:116-128(2013).
CC -!- FUNCTION: Catalyzes the transfer of a two-carbon ketol group from a
CC ketose donor to an aldose acceptor, likely via a covalent intermediate
CC with the cofactor thiamine pyrophosphate. Can use L-erythrulose as
CC donor and D-ribose-5-phosphate as acceptor substrates, forming
CC glycolaldehyde and D-sedoheptulose-7-phosphate. For synthetic purposes,
CC is able to use hydroxypyruvate (HPA) as donor substrate, making the
CC reaction irreversible due to the release of carbon dioxide, and various
CC aldehydes as acceptor substrates, which leads to the corresponding
CC ketoses. Thus, using hydroxypyruvate as donor and three different
CC aldehydes as acceptors, i.e. glycolaldehyde, D-glyceraldehyde and
CC butyraldehyde, the enzyme stereoselectively forms the corresponding
CC products L-erythrulose, D-xylulose and (3S)-1,3-dihydroxyhexan-2-one,
CC respectively. {ECO:0000269|Ref.2}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=D-glyceraldehyde 3-phosphate + D-sedoheptulose 7-phosphate =
CC aldehydo-D-ribose 5-phosphate + D-xylulose 5-phosphate;
CC Xref=Rhea:RHEA:10508, ChEBI:CHEBI:57483, ChEBI:CHEBI:57737,
CC ChEBI:CHEBI:58273, ChEBI:CHEBI:59776; EC=2.2.1.1;
CC Evidence={ECO:0000250|UniProtKB:P27302};
CC -!- COFACTOR:
CC Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000305|Ref.2};
CC Note=Binds 1 Mg(2+) ion per subunit. {ECO:0000250|UniProtKB:P27302};
CC -!- COFACTOR:
CC Name=thiamine diphosphate; Xref=ChEBI:CHEBI:58937;
CC Evidence={ECO:0000305|Ref.2};
CC Note=Binds 1 thiamine pyrophosphate per subunit.
CC {ECO:0000250|UniProtKB:P27302};
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=5.2 mM for L-erythrulose (at 25 degrees Celsius)
CC {ECO:0000269|Ref.2};
CC KM=0.20 mM for D-ribose 5-phosphate (at 25 degrees Celsius)
CC {ECO:0000269|Ref.2};
CC KM=8.0 mM for L-erythrulose (at 50 degrees Celsius)
CC {ECO:0000269|Ref.2};
CC KM=0.13 mM for D-ribose 5-phosphate (at 50 degrees Celsius)
CC {ECO:0000269|Ref.2};
CC Vmax=1.0 umol/min/mg enzyme for the reaction with L-erythrulose and
CC D-ribose 5-phosphate as substrates (at 25 degrees Celsius)
CC {ECO:0000269|Ref.2};
CC Vmax=8.4 umol/min/mg enzyme for the reaction with L-erythrulose and
CC D-ribose 5-phosphate as substrates (at 50 degrees Celsius)
CC {ECO:0000269|Ref.2};
CC pH dependence:
CC Optimum pH is 7-8. {ECO:0000269|Ref.2};
CC Temperature dependence:
CC Optimum temperature is around 60-70 degrees Celsius. Thermostable.
CC Retains 100% activity for one week at 50 degrees Celsius and for 3
CC days at 65 degrees Celsius. Activity decreases rapidly at 75 degrees
CC Celsius (half-life is about 15 minutes), and at 85 degrees Celsius
CC loses its activity immediately. {ECO:0000269|Ref.2};
CC -!- SUBUNIT: Homodimer. {ECO:0000250|UniProtKB:P27302}.
CC -!- BIOTECHNOLOGY: The thermostability, stereoselectivity and wide
CC substrate specificity of this enzyme offers good opportunities for
CC applications in biocatalysis for ketose and chiral threo-diols
CC synthesis. {ECO:0000305|Ref.2}.
CC -!- SIMILARITY: Belongs to the transketolase family. {ECO:0000305}.
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DR EMBL; LN871220; CTQ31223.1; -; Genomic_DNA.
DR AlphaFoldDB; A0A0I9QGZ2; -.
DR SMR; A0A0I9QGZ2; -.
DR BRENDA; 2.2.1.1; 623.
DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR GO; GO:0004802; F:transketolase activity; IDA:UniProtKB.
DR CDD; cd02012; TPP_TK; 1.
DR Gene3D; 3.40.50.920; -; 1.
DR InterPro; IPR029061; THDP-binding.
DR InterPro; IPR009014; Transketo_C/PFOR_II.
DR InterPro; IPR005475; Transketolase-like_Pyr-bd.
DR InterPro; IPR005478; Transketolase_bac-like.
DR InterPro; IPR020826; Transketolase_BS.
DR InterPro; IPR033248; Transketolase_C.
DR InterPro; IPR033247; Transketolase_fam.
DR InterPro; IPR005474; Transketolase_N.
DR PANTHER; PTHR43522; PTHR43522; 1.
DR Pfam; PF02779; Transket_pyr; 1.
DR Pfam; PF02780; Transketolase_C; 1.
DR Pfam; PF00456; Transketolase_N; 1.
DR SMART; SM00861; Transket_pyr; 1.
DR SUPFAM; SSF52518; SSF52518; 2.
DR SUPFAM; SSF52922; SSF52922; 1.
DR TIGRFAMs; TIGR00232; tktlase_bact; 1.
DR PROSITE; PS00801; TRANSKETOLASE_1; 1.
DR PROSITE; PS00802; TRANSKETOLASE_2; 1.
PE 1: Evidence at protein level;
KW Magnesium; Metal-binding; Thiamine pyrophosphate; Transferase.
FT CHAIN 1..668
FT /note="Transketolase"
FT /id="PRO_0000435900"
FT ACT_SITE 412
FT /note="Proton donor"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 28
FT /ligand="substrate"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 68
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 116..118
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 157
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 158
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 187
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 187
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 189
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 263
FT /ligand="substrate"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 263
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 358
FT /ligand="substrate"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 385
FT /ligand="substrate"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 438
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 462
FT /ligand="substrate"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 470
FT /ligand="substrate"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 474
FT /ligand="substrate"
FT /evidence="ECO:0000250|UniProtKB:P27302"
FT BINDING 521
FT /ligand="substrate"
FT /evidence="ECO:0000250|UniProtKB:P27302"
SQ SEQUENCE 668 AA; 71932 MW; 751631D4E86EEF69 CRC64;
MAHSIEELAI TTIRTLSIDA IEKAKSGHPG MPMGAAPMAY TLWTKFMNHN PANPNWFNRD
RFVLSAGHGS MLLYSLLHLS GYDVSMDDLK QFRQWGSKTP GHPEYGHTPG VEATTGPLGQ
GIAMAVGMAM AERHLAATYN RDGFEIINHY TYAICGDGDL MEGVASEAAS LAGHLKLGRL
IVLYDSNDIS LDGELNLSFS ENVAQRFQAY GWQYLRVEDG NNIEEIAKAL EEARADLSRP
TLIEVKTTIG YGAPNKAGTS GVHGAPLGAQ EAKLTKEAYR WTFAEDFYVP EEVYAHFRAT
VQEPGAKKEA KWNEQLAAYE QAHPELAAQL KRAIEGKLPD GWEASLPVYE AGKSLATRSS
SGEVINAIAK AVPQLFGGSA DLASSNKTLI KGGGNFLPDS YEGRNVWFGV REFAMGAALN
GMALHGGLKV FGGTFFVFSD YLRPAIRLAA LMGLPVIYVL THDSIAVGED GPTHEPIEHL
ASLRAMPNLS VIRPADANET AAAWRLALES TDKPTALVLT RQDVPTLAAT AELAYEGVKK
GAYVVSPAKN GAPEALLLAT GSEVGLAVKA QEALAAEGIH VSVISMPSWD RFEAQPKSYR
DEVLPPAVTK RLAIEMGASL GWERYVGAEG DILAIDRFGA SAPGEKIMAE YGFTVDNVVR
RTKALLGK
