TKTC_SPIOL
ID TKTC_SPIOL Reviewed; 741 AA.
AC O20250;
DT 21-JUN-2005, integrated into UniProtKB/Swiss-Prot.
DT 01-JAN-1998, sequence version 1.
DT 03-AUG-2022, entry version 93.
DE RecName: Full=Transketolase, chloroplastic;
DE Short=TK;
DE EC=2.2.1.1;
DE Flags: Precursor;
OS Spinacia oleracea (Spinach).
OC Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC Caryophyllales; Chenopodiaceae; Chenopodioideae; Anserineae; Spinacia.
OX NCBI_TaxID=3562;
RN [1] {ECO:0000305, ECO:0000312|EMBL:AAD10219.1}
RP NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, AND CATALYTIC ACTIVITY.
RC TISSUE=Seedling {ECO:0000312|EMBL:AAD10219.1};
RX PubMed=8980496; DOI=10.1007/bf00019099;
RA Flechner A., Dressen U., Westhoff P., Henze K., Schnarrenberger C.,
RA Martin W.;
RT "Molecular characterization of transketolase (EC 2.2.1.1) active in the
RT Calvin cycle of spinach chloroplasts.";
RL Plant Mol. Biol. 32:475-484(1996).
RN [2] {ECO:0000305}
RP PROTEIN SEQUENCE OF 67-83, BIOPHYSICOCHEMICAL PROPERTIES, SUBUNIT, AND
RP SUBCELLULAR LOCATION.
RC STRAIN=cv. Matador {ECO:0000269|PubMed:9523694};
RC TISSUE=Leaf {ECO:0000269|PubMed:9523694};
RX PubMed=9523694; DOI=10.1046/j.1432-1327.1998.2520237.x;
RA Teige M., Melzer M., Suess K.-H.;
RT "Purification, properties and in situ localization of the amphibolic
RT enzymes D-ribulose 5-phosphate 3-epimerase and transketolase from spinach
RT chloroplasts.";
RL Eur. J. Biochem. 252:237-244(1998).
CC -!- FUNCTION: Catalyzes the reversible transfer of a two-carbon ketol group
CC from fructose-6-phosphate or sedoheptulose-7-phosphate to
CC glyceraldehyde-3-phosphate to yield xylulose-5-phosphate and erythrose-
CC 4-phosphate or ribose-5-phosphate, respectively.
CC {ECO:0000269|PubMed:8980496, ECO:0000303|PubMed:8980496}.
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:0000269|PubMed:8980496};
CC -!- COFACTOR:
CC Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000250};
CC Name=Ca(2+); Xref=ChEBI:CHEBI:29108; Evidence={ECO:0000250};
CC Name=Mn(2+); Xref=ChEBI:CHEBI:29035; Evidence={ECO:0000250};
CC Name=Co(2+); Xref=ChEBI:CHEBI:48828; Evidence={ECO:0000250};
CC Note=Binds 1 Mg(2+) ion per subunit. Can also utilize other divalent
CC metal cations, such as Ca(2+), Mn(2+) and Co(2+). {ECO:0000250};
CC -!- COFACTOR:
CC Name=thiamine diphosphate; Xref=ChEBI:CHEBI:58937;
CC Evidence={ECO:0000250};
CC Note=Binds 1 thiamine pyrophosphate per subunit. {ECO:0000250};
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=67 uM for xylulose 5-phosphate {ECO:0000269|PubMed:9523694};
CC KM=330 uM for ribose 5-phosphate {ECO:0000269|PubMed:9523694};
CC pH dependence:
CC Optimum pH is 8.0. {ECO:0000269|PubMed:9523694};
CC -!- PATHWAY: Carbohydrate biosynthesis; Calvin cycle.
CC -!- SUBUNIT: Homodimer. {ECO:0000269|PubMed:9523694}.
CC -!- SUBCELLULAR LOCATION: Plastid, chloroplast thylakoid membrane
CC {ECO:0000269|PubMed:9523694}.
CC -!- SIMILARITY: Belongs to the transketolase family.
CC {ECO:0000269|PubMed:8980496}.
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DR EMBL; L76554; AAD10219.1; -; mRNA.
DR PIR; T09015; T09015.
DR AlphaFoldDB; O20250; -.
DR SMR; O20250; -.
DR PRIDE; O20250; -.
DR SABIO-RK; O20250; -.
DR UniPathway; UPA00116; -.
DR GO; GO:0009535; C:chloroplast thylakoid membrane; IDA:UniProtKB.
DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR GO; GO:0004802; F:transketolase activity; IDA:UniProtKB.
DR GO; GO:0009051; P:pentose-phosphate shunt, oxidative branch; NAS:UniProtKB.
DR GO; GO:0019253; P:reductive pentose-phosphate cycle; NAS: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; 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.
PE 1: Evidence at protein level;
KW Calcium; Chloroplast; Direct protein sequencing; Magnesium; Membrane;
KW Metal-binding; Plastid; Thiamine pyrophosphate; Thylakoid; Transferase;
KW Transit peptide.
FT TRANSIT 1..66
FT /note="Chloroplast"
FT /evidence="ECO:0000269|PubMed:9523694"
FT CHAIN 67..741
FT /note="Transketolase, chloroplastic"
FT /id="PRO_0000035752"
FT REGION 1..33
FT /note="Disordered"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
FT ACT_SITE 488
FT /note="Proton donor"
FT /evidence="ECO:0000250"
FT BINDING 103
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT BINDING 143
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250"
FT BINDING 192..194
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250"
FT BINDING 233
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250"
FT BINDING 234
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250"
FT BINDING 263
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250"
FT BINDING 263
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250"
FT BINDING 265
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250"
FT BINDING 340
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT BINDING 340
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250"
FT BINDING 434
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT BINDING 461
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT BINDING 488
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250"
FT BINDING 515
FT /ligand="thiamine diphosphate"
FT /ligand_id="ChEBI:CHEBI:58937"
FT /evidence="ECO:0000250"
FT BINDING 539
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT BINDING 547
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT BINDING 598
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT SITE 103
FT /note="Important for catalytic activity"
FT /evidence="ECO:0000250"
FT SITE 340
FT /note="Important for catalytic activity"
FT /evidence="ECO:0000250"
FT CONFLICT 77
FT /note="I -> D (in Ref. 2; AA sequence)"
FT /evidence="ECO:0000305"
FT CONFLICT 83
FT /note="K -> G (in Ref. 2; AA sequence)"
FT /evidence="ECO:0000305"
SQ SEQUENCE 741 AA; 80281 MW; 28871ED8568EAC8B CRC64;
MAASSSLSTL SHHQTLLSHP KTHLPTTPAS SLLVPTTSSK VNGVLLKSTS SSRRLRVGSA
SAVVRAAAVE ALESTDIDQL VEKSVNTIRF LAIDAVEKAN SGHPGLPMGC APMGHILYDE
IMRYNPKNPY WFNRDRFVLS AGHGCMLQYA LLHLAGYDSV LEEDLKTFRQ WGSRIPGHPE
NFETPGVEVT TGPLGQGIAN AVGLALAEKH LAARFNKPDA EIVDHYTYVI LGDGCQMEGI
AQEACSLAGH WGLGKLIAFY DDNHISIDGD TAIAFTESVD LRFEALGWHV IWVKNGNTGY
DEIRAAIKEA KTVTDKPTLI KVTTTIGFGS PNKSNSYSVH GSALGSKEVE ATRQNLGWPY
EPFHVPEEVK KHWSRHTPEG ASLEAEWNTK FAEYEKKYPE DATEFKSITT GEFPAGWEKA
LPTYTPETPG DATRNLSQQC LNALAKVIPG LLGGSADLAS SNMTLLKMFG DFRRTHRKKE
TFRFGVREHG MGAICNGICL HSPGFVPYCA TFFVFTDYMR GAMRISALSE AGVIYVMTHD
SIGLGEDGPT HQPIEALSKF PAMPNILMLR PADGNETAGS YKVAVENRKT PSILALSRKK
LPNLPGTSIE GVEKGGYTIT DNSSGNKPDV ILIGTGSELE IAAKAGDELR KEGKAVRVVS
FVSWELFEKQ SDEYKESVLP SDVTARVSIE AGSTFGWHKI VGSKGKAIGI DKFGASAPAG
KIYQEYGITV EAVVEAAKSV C
