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Escherichia coli K-12 substr. MG1655 Enzyme: transketolase II



Gene: tktB Accession Numbers: EG12100 (EcoCyc), b2465, ECK2460

Synonyms: TK II

Regulation Summary Diagram: ?

Subunit composition of transketolase II = [TktB]
         transketolase II = TktB

Summary:
Transketolase catalyzes the reversible transfer of a ketol group between several donor and acceptor substrates. E. coli contains two transketolase isozymes, TktA and TktB. TktB is responsible for the minor transketolase activity [Iida93].

Overproduction of TktB suppresses the tktA mutant phenotype [Iida93]. A tktA tktB double mutant requires pyridoxine (or 4-hydroxy-L-threonine or glycolaldehyde), aromatic amino acids and vitamins for growth [Zhao94].

Expression of tktB is increased in a tyrR mutant in the presence of phenylalanine [Polen05]. tktB expression is increased in stationary phase and positively regulated by RpoS [Jung05, Rahman08] and ppGpp [Harinarayanan08]. Expression of tktA and tktB is complementary, resulting in approximately constant levels of transketolase expression throughout growth [Rahman08]. A tktB mutant has lower acetate yield, but increased biomass yield under aerobic growth conditions [Rahman08a]. Levels of TktB protein increase during osmotic stress under aerobic, but not anaerobic growth conditions [Weber06].

TktB appears to be associated with the degradosome [Regonesi06] and may connect carbon metabolism to replication [Maciag11a]. Filament formation of a dnaE486 mutant is partially suppressed by deletion of tktB [MaciagDorszynsk12].

The subunit structure of transketolase II (TktB) has not been explicitly determined. However, transketolase I (TktA) is homodimeric [Sprenger95].

Review: [Sprenger95b]

Locations: cytosol

Map Position: [2,577,658 -> 2,579,661] (55.56 centisomes)
Length: 2004 bp / 667 aa

Molecular Weight of Polypeptide: 73.043 kD (from nucleotide sequence), 72.0 kD (experimental) [Iida93 ]

Isozyme Sequence Similarity [Comment 1]:
transketolase I: YES

Unification Links: ASAP:ABE-0008117 , CGSC:29992 , DIP:DIP-10999N , EchoBASE:EB2024 , EcoGene:EG12100 , EcoliWiki:b2465 , ModBase:P33570 , OU-Microarray:b2465 , PortEco:tktB , PR:PRO_000024073 , Pride:P33570 , Protein Model Portal:P33570 , RefSeq:NP_416960 , RegulonDB:EG12100 , SMR:P33570 , String:511145.b2465 , Swiss-Model:P33570 , UniProt:P33570

Relationship Links: InterPro:IN-FAMILY:IPR005474 , InterPro:IN-FAMILY:IPR005475 , InterPro:IN-FAMILY:IPR005476 , InterPro:IN-FAMILY:IPR005478 , InterPro:IN-FAMILY:IPR009014 , InterPro:IN-FAMILY:IPR015941 , InterPro:IN-FAMILY:IPR020826 , Pfam:IN-FAMILY:PF00456 , Pfam:IN-FAMILY:PF02779 , Pfam:IN-FAMILY:PF02780 , Prosite:IN-FAMILY:PS00801 , Prosite:IN-FAMILY:PS00802 , Smart:IN-FAMILY:SM00861

Gene-Reaction Schematic: ?

Genetic Regulation Schematic: ?

GO Terms:

Biological Process: GO:0009052 - pentose-phosphate shunt, non-oxidative branch Inferred from experiment [Iida93]
GO:0008152 - metabolic process Inferred by computational analysis [GOA01]
Molecular Function: GO:0004802 - transketolase activity Inferred from experiment Inferred by computational analysis [GOA01a, GOA01, Iida93]
GO:0003824 - catalytic activity Inferred by computational analysis [GOA01]
GO:0016740 - transferase activity Inferred by computational analysis [UniProtGOA11]
GO:0046872 - metal ion binding Inferred by computational analysis [UniProtGOA11]
Cellular Component: GO:0005829 - cytosol Inferred from experiment Inferred by computational analysis [DiazMejia09, Ishihama08]

MultiFun Terms: metabolism carbon utilization carbon compounds
metabolism central intermediary metabolism non-oxidative branch, pentose pathway

Essentiality data for tktB knockouts: ?

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB enriched Yes 37 Aerobic 6.95   Yes [Gerdes03, Comment 2]
LB Lennox Yes 37 Aerobic 7   Yes [Baba06, Comment 3]
M9 medium with 1% glycerol Yes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 4]
MOPS medium with 0.4% glucose Yes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 3]
Yes [Feist07, Comment 5]

Credits:
Last-Curated ? 04-Oct-2012 by Keseler I , SRI International


Enzymatic reaction of: transketolase

Synonyms: sedoheptulose-7-phosphate:D-glyceraldehyde-3-phosphate glycoaldehydetransferase

EC Number: 2.2.1.1

D-sedoheptulose 7-phosphate + D-glyceraldehyde 3-phosphate <=> D-ribose 5-phosphate + D-xylulose 5-phosphate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

This reaction is reversible.

In Pathways: pentose phosphate pathway , pentose phosphate pathway (non-oxidative branch)


Enzymatic reaction of: transketolase

Synonyms: D-fructose 6-phosphate:D-glyceraldehyde-3-phosphate glycolaldehydetransferase

EC Number: 2.2.1.1

D-erythrose 4-phosphate + D-xylulose 5-phosphate <=> β-D-fructofuranose 6-phosphate + D-glyceraldehyde 3-phosphate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

This reaction is reversible.

In Pathways: pentose phosphate pathway , pentose phosphate pathway (non-oxidative branch)


Sequence Features

Feature Class Location Attached Group Citations Comment
Cleavage-of-Initial-Methionine 1  
[Iida93]
 
Amino-Acid-Sites-That-Bind 25  
[UniProt12]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.
Amino-Acid-Sites-That-Bind 65  
[UniProt12]
UniProt: Thiamine pyrophosphate; Non-Experimental Qualifier: by similarity.
Nucleotide-Phosphate-Binding-Region 113 -> 115 thiamin diphosphate
[UniProt14]
UniProt: Thiamine pyrophosphate; Non-Experimental Qualifier: by similarity.
Metal-Binding-Site 154  
[UniProt10a]
UniProt: Calcium; Non-Experimental Qualifier: by similarity;
Amino-Acid-Sites-That-Bind 155  
[UniProt12]
UniProt: Thiamine pyrophosphate; via amide nitrogen; Non-Experimental Qualifier: by similarity.
Metal-Binding-Site 184  
[UniProt10a]
UniProt: Calcium; Non-Experimental Qualifier: by similarity;
Metal-Binding-Site 186  
[UniProt10a]
UniProt: Calcium; via carbonyl oxygen; Non-Experimental Qualifier: by similarity;
Amino-Acid-Sites-That-Bind 260  
[UniProt12]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.
Acetylation-Modification 342  
[Zhang09a, UniProt11]
UniProt: N6-acetyllysine.
Amino-Acid-Sites-That-Bind 357  
[UniProt12]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.
Amino-Acid-Sites-That-Bind 384  
[UniProt12]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.
Active-Site 410  
[UniProt12]
UniProt: Proton donor; Non-Experimental Qualifier: by similarity.
Amino-Acid-Sites-That-Bind 436  
[UniProt12]
UniProt: Thiamine pyrophosphate; Non-Experimental Qualifier: by similarity.
Amino-Acid-Sites-That-Bind 460  
[UniProt12]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.
Amino-Acid-Sites-That-Bind 468  
[UniProt12]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.
Amino-Acid-Sites-That-Bind 519  
[UniProt12]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.


Gene Local Context (not to scale): ?

Transcription Units:

Notes:

History:
10/20/97 Gene b2465 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG12100; confirmed by SwissProt match.


References

Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554

DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114

Feist07: Feist AM, Henry CS, Reed JL, Krummenacker M, Joyce AR, Karp PD, Broadbelt LJ, Hatzimanikatis V, Palsson BO (2007). "A genome-scale metabolic reconstruction for Escherichia coli K-12 MG1655 that accounts for 1260 ORFs and thermodynamic information." Mol Syst Biol 3;121. PMID: 17593909

Gerdes03: Gerdes SY, Scholle MD, Campbell JW, Balazsi G, Ravasz E, Daugherty MD, Somera AL, Kyrpides NC, Anderson I, Gelfand MS, Bhattacharya A, Kapatral V, D'Souza M, Baev MV, Grechkin Y, Mseeh F, Fonstein MY, Overbeek R, Barabasi AL, Oltvai ZN, Osterman AL (2003). "Experimental determination and system level analysis of essential genes in Escherichia coli MG1655." J Bacteriol 185(19);5673-84. PMID: 13129938

GOA01: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

GOA01a: GOA, MGI (2001). "Gene Ontology annotation based on Enzyme Commission mapping." Genomics 74;121-128.

Harinarayanan08: Harinarayanan R, Murphy H, Cashel M (2008). "Synthetic growth phenotypes of Escherichia coli lacking ppGpp and transketolase A (tktA) are due to ppGpp-mediated transcriptional regulation of tktB." Mol Microbiol 69(4);882-94. PMID: 18532980

Iida93: Iida A, Teshiba S, Mizobuchi K (1993). "Identification and characterization of the tktB gene encoding a second transketolase in Escherichia coli K-12." J Bacteriol 1993;175(17);5375-83. PMID: 8396116

Ishihama08: Ishihama Y, Schmidt T, Rappsilber J, Mann M, Hartl FU, Kerner MJ, Frishman D (2008). "Protein abundance profiling of the Escherichia coli cytosol." BMC Genomics 9;102. PMID: 18304323

Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394

Jung05: Jung IL, Phyo KH, Kim IG (2005). "RpoS-mediated growth-dependent expression of the Escherichia coli tkt genes encoding transketolases isoenzymes." Curr Microbiol 50(6);314-8. PMID: 15968503

Maciag11a: Maciag M, Nowicki D, Janniere L, Szalewska-Palasz A, Wegrzyn G (2011). "Genetic response to metabolic fluctuations: correlation between central carbon metabolism and DNA replication in Escherichia coli." Microb Cell Fact 10;19. PMID: 21453533

MaciagDorszynsk12: Maciag-Dorszynska M, Ignatowska M, Janniere L, Wegrzyn G, Szalewska-Palasz A (2012). "Mutations in central carbon metabolism genes suppress defects in nucleoid position and cell division of replication mutants in Escherichia coli." Gene 503(1);31-5. PMID: 22565187

Polen05: Polen T, Kramer M, Bongaerts J, Wubbolts M, Wendisch VF (2005). "The global gene expression response of Escherichia coli to L-phenylalanine." J Biotechnol 115(3);221-37. PMID: 15639085

Rahman08: Rahman M, Hasan MR, Shimizu K (2008). "Growth phase-dependent changes in the expression of global regulatory genes and associated metabolic pathways in Escherichia coli." Biotechnol Lett 30(5);853-60. PMID: 18175070

Rahman08a: Rahman M, Shimizu K (2008). "Altered acetate metabolism and biomass production in several Escherichia coli mutants lacking rpoS-dependent metabolic pathway genes." Mol Biosyst 4(2);160-9. PMID: 18213409

Regonesi06: Regonesi ME, Del Favero M, Basilico F, Briani F, Benazzi L, Tortora P, Mauri P, Deho G (2006). "Analysis of the Escherichia coli RNA degradosome composition by a proteomic approach." Biochimie 88(2);151-61. PMID: 16139413

Sprenger95: Sprenger GA, Schorken U, Sprenger G, Sahm H (1995). "Transketolase A of Escherichia coli K12. Purification and properties of the enzyme from recombinant strains." Eur J Biochem 1995;230(2);525-32. PMID: 7607225

Sprenger95b: Sprenger GA (1995). "Genetics of pentose-phosphate pathway enzymes of Escherichia coli K-12." Arch Microbiol 1995;164(5);324-30. PMID: 8572885

UniProt10a: UniProt Consortium (2010). "UniProt version 2010-07 released on 2010-06-15 00:00:00." Database.

UniProt11: UniProt Consortium (2011). "UniProt version 2011-06 released on 2011-06-30 00:00:00." Database.

UniProt12: UniProt Consortium (2012). "UniProt version 2012-09 released on 2012-09-12 00:00:00." Database.

UniProt14: UniProt Consortium (2014). "UniProt version 2014-01 released on 2014-01-01 00:00:00." Database.

UniProtGOA11: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

Weber06: Weber A, Kogl SA, Jung K (2006). "Time-dependent proteome alterations under osmotic stress during aerobic and anaerobic growth in Escherichia coli." J Bacteriol 188(20);7165-75. PMID: 17015655

Zhang09a: Zhang J, Sprung R, Pei J, Tan X, Kim S, Zhu H, Liu CF, Grishin NV, Zhao Y (2009). "Lysine acetylation is a highly abundant and evolutionarily conserved modification in Escherichia coli." Mol Cell Proteomics 8(2);215-25. PMID: 18723842

Zhao94: Zhao G, Winkler ME (1994). "An Escherichia coli K-12 tktA tktB mutant deficient in transketolase activity requires pyridoxine (vitamin B6) as well as the aromatic amino acids and vitamins for growth." J Bacteriol 1994;176(19);6134-8. PMID: 7928977

Other References Related to Gene Regulation

Lacour04: Lacour S, Landini P (2004). "SigmaS-dependent gene expression at the onset of stationary phase in Escherichia coli: function of sigmaS-dependent genes and identification of their promoter sequences." J Bacteriol 186(21);7186-95. PMID: 15489429

Marzan13: Marzan LW, Hasan CM, Shimizu K (2013). "Effect of acidic condition on the metabolic regulation of Escherichia coli and its phoB mutant." Arch Microbiol 195(3);161-71. PMID: 23274360


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
Page generated by SRI International Pathway Tools version 18.5 on Fri Nov 21, 2014, BIOCYC14A.