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discounted EARLY registration ends Dec 31, 2014
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discounted EARLY registration ends Dec 31, 2014
Metabolic Modeling Tutorial
discounted EARLY registration ends Dec 31, 2014
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MetaCyc Enzyme: transketolase II

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

Synonyms: TK II

Species: Escherichia coli K-12 substr. MG1655

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 [Maci11]. Filament formation of a dnaE486 mutant is partially suppressed by deletion of tktB [Maci12].

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

Review: [Sprenger95a]

Locations: cytosol

Map Position: [2,577,658 -> 2,579,661]

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

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: ?

GO Terms:

Biological Process: GO:0009052 - pentose-phosphate shunt, non-oxidative branch Inferred from experiment [Iida93]
GO:0008152 - metabolic process Inferred by computational analysis [GOA01a]
Molecular Function: GO:0004802 - transketolase activity Inferred from experiment Inferred by computational analysis [GOA01, GOA01a, Iida93]
GO:0003824 - catalytic activity Inferred by computational analysis [GOA01a]
GO:0016740 - transferase activity Inferred by computational analysis [UniProtGOA11a]
GO:0046872 - metal ion binding Inferred by computational analysis [UniProtGOA11a]
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

Credits:
Imported from EcoCyc 16-Sep-2014 by Paley S , 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 , photosynthetic 3-hydroxybutyrate biosynthesis (engineered) , pentose phosphate pathway (non-oxidative branch)

Credits:
Imported from EcoCyc 16-Sep-2014 by Paley S , SRI International


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 , photosynthetic 3-hydroxybutyrate biosynthesis (engineered) , pentose phosphate pathway (non-oxidative branch)

Credits:
Imported from EcoCyc 16-Sep-2014 by Paley S , SRI International


Sequence Features

Feature Class Location Attached Group Citations Comment
Cleavage-of-Initial-Methionine 1  
[Iida93]
 
Amino-Acid-Sites-That-Bind 25  
[UniProt12a]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.
Amino-Acid-Sites-That-Bind 65  
[UniProt12a]
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  
[UniProt10]
UniProt: Calcium; Non-Experimental Qualifier: by similarity;
Amino-Acid-Sites-That-Bind 155  
[UniProt12a]
UniProt: Thiamine pyrophosphate; via amide nitrogen; Non-Experimental Qualifier: by similarity.
Metal-Binding-Site 184  
[UniProt10]
UniProt: Calcium; Non-Experimental Qualifier: by similarity;
Metal-Binding-Site 186  
[UniProt10]
UniProt: Calcium; via carbonyl oxygen; Non-Experimental Qualifier: by similarity;
Amino-Acid-Sites-That-Bind 260  
[UniProt12a]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.
Acetylation-Modification 342  
[Zhang09a, UniProt11a]
UniProt: N6-acetyllysine.
Amino-Acid-Sites-That-Bind 357  
[UniProt12a]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.
Amino-Acid-Sites-That-Bind 384  
[UniProt12a]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.
Active-Site 410  
[UniProt12a]
UniProt: Proton donor; Non-Experimental Qualifier: by similarity.
Amino-Acid-Sites-That-Bind 436  
[UniProt12a]
UniProt: Thiamine pyrophosphate; Non-Experimental Qualifier: by similarity.
Amino-Acid-Sites-That-Bind 460  
[UniProt12a]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.
Amino-Acid-Sites-That-Bind 468  
[UniProt12a]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.
Amino-Acid-Sites-That-Bind 519  
[UniProt12a]
UniProt: Substrate; Non-Experimental Qualifier: by similarity.

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


References

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

GOA01: GOA, MGI (2001). "Gene Ontology annotation based on Enzyme Commission mapping." Genomics 74;121-128.

GOA01a: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

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

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

Maci11: Maciąg M, Nowicki D, Janniere L, Szalewska-Palasz A, Węgrzyn 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

Maci12: Maciąg-Dorszyńska M, Ignatowska M, Janniere L, Węgrzyn 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

Sprenger95a: Sprenger GA (1995). "Genetics of pentose-phosphate pathway enzymes of Escherichia coli K-12." Arch Microbiol 1995;164(5);324-30. PMID: 8572885

UniProt10: UniProt Consortium (2010). "UniProt version 2010-07 released on 2010-06-15 00:00:00." Database.

UniProt11a: UniProt Consortium (2011). "UniProt version 2011-06 released on 2011-06-30 00:00:00." Database.

UniProt12a: 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.

UniProtGOA11a: 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


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Sun Nov 23, 2014, BIOCYC13A.