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Escherichia coli K-12 substr. MG1655 Polypeptide: acetolactate synthase II, large subunit, N-ter fragment (pseudogene)




Gene: ilvG_1 Accession Numbers: G8221 (EcoCyc), b3767, ECK3760

Synonyms: ilvG, ilvO

Regulation Summary Diagram

Regulation summary diagram for ilvG_1

Component of: acetohydroxybutanoate synthase / acetolactate synthase (extended summary available)

Summary:
ilvG is not expressed in the canonical, sequenced E. coli K-12 strain due to an internal frameshift mutation that effectively cuts it in half [Favre76, Gray81]. Mutations that remove a single nucleotide or add two nucleotides can revert a strain to allow wild-type production of IlvG [Lawther81, Lawther82]. Based on a similar example in S. typhimurium, it has been suggested that this disabling mutation in ilvG is specific to the lab isolate, and is not representative of natural E. coli strains [Burns95].

E. coli K-12 with the ilvG mutation undergo oscillating cycles of isoleucine starvation due to abberant regulation of isoleucine biosynthesis. This is alleviated by restoration of ilvG expression [Andersen01].

ilvG expression increases during growth on acetate [Oh00].

ptsN knockout phenotypes relating to nitrogen source utilization regulation was observed only in strains lacking functional ilvG [Reaves11].

For the second half of this disrupted protein, see acetolactate synthase II, large subunit, C-ter fragment (pseudogene).

In non-K-12 strains site-directed mutagenesis and crystallographic studies of IlvG have helped define the catalytic mechanism [Steinmetz10, Vyazmensky11, Niu11].

Gene Citations: [Sameshima89, Parekh97, Driver85, Lawther87]

Map Position: [3,948,583 -> 3,949,566] (85.1 centisomes, 306°)
Length: 984 bp / 327 aa

Molecular Weight of Polypeptide: 34.507 kD (from nucleotide sequence)

Unification Links: EcoliWiki:b3767, OU-Microarray:b3767, PortEco:ilvG_1, PR:PRO_000023006, RegulonDB:G8221

Relationship Links: EcoGene:RELATED-TO:EG10498, ModBase:RELATED-TO:P00892, Swiss-Model:RELATED-TO:P00892, UniProt:RELATED-TO:P00892

In Paralogous Gene Group: 143 (4 members)

Gene-Reaction Schematic

Gene-Reaction Schematic

Genetic Regulation Schematic

Genetic regulation schematic for ilvG_1


GO Terms:
Molecular Function:
Inferred by computational analysisGO:0003984 - acetolactate synthase activity []

Gene Class: Pseudo-GenesInterrupted-Genes

Essentiality data for ilvG_1 knockouts:

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB enrichedYes 37 Aerobic 6.95   Yes [Gerdes03, Comment 1]
LB LennoxYes 37 Aerobic 7   Yes [Baba06, Comment 2]
M9 medium with 1% glycerolYes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 3]
MOPS medium with 0.4% glucoseYes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 2]

Credits:
Last-Curated 17-Oct-2013 by Kubo A, SRI International


Subunit of: acetohydroxybutanoate synthase / acetolactate synthase

Synonyms: AHAS, AHAS II, acetohydroxy acid synthase II, acetohydroxybutanoate synthase II, acetolactate synthase II

Subunit composition of acetohydroxybutanoate synthase / acetolactate synthase = [IlvG_1][IlvG_2][IlvM]
         acetolactate synthase II, large subunit, N-ter fragment (pseudogene) = IlvG_1 (extended summary available)
         acetolactate synthase II, large subunit, C-ter fragment (pseudogene) = IlvG_2 (extended summary available)

Summary:
Acetohydroxyacid synthase II (AHAS II) encoded by ilvG and ilvM catalyzes the biosynthesis of α-aceto-α-hydroxybutyrate and α-acetolactate. AHAS II is not found in E. coli K-12 due to a mutation in ilvG, although it is found in other E. coli strains. See the entries for acetolactate synthase II, large subunit, N-ter fragment (pseudogene) and acetolactate synthase II, large subunit, C-ter fragment (pseudogene) for more information.

In non-K-12 strains AHAS II is a bifunctional enzyme that catalyzes the biosynthesis of α-aceto-α-hydroxybutyrate for the isoleucine pathway and of α-acetolactate for the valine pathway [Dailey86]. Both the large catalytic subunit IlvG and the small regulatory subunit IlvM are required for this activity, though the exact stoichiometry of the IlvM subunit is unclear [Hill97, Lu87]. The kinetics of AHAS II have been evaluated [Hill97]. Interactions between the large and small subunits of the three AHAS isozymes have been studied [Vyazmensky09].

Review: [Barak12]

Credits:
Last-Curated 24-Feb-2006 by Shearer A, SRI International


Enzymatic reaction of: acetohydroxybutanoate synthase

Inferred from experiment

Synonyms: acetolactate pyruvate-lyase (carboxylating), acetohydroxy acid synthase

EC Number: 2.2.1.6

pyruvate + 2-oxobutanoate + H+ → (S)-2-aceto-2-hydroxybutanoate + CO2

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

Alternative Substrates for pyruvate: 2-oxobutanoate, 2-oxobutanoate

In Pathways: superpathway of branched amino acid biosynthesis, superpathway of L-threonine metabolism, L-isoleucine biosynthesis I (from threonine)

Cofactors or Prosthetic Groups: thiamine diphosphate, FAD [Hill97], FAD [Hill97]

Inhibitors (Unknown Mechanism): L-leucine, L-valine

Enzymatic reaction of: acetolactate synthase

Inferred from experiment

Synonyms: acetolactate pyruvate-lyase (carboxylating), acetohydroxy acid synthase

EC Number: 2.2.1.6

2 pyruvate + H+ → (S)-2-acetolactate + CO2

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

This reaction is reversible.

In Pathways: superpathway of branched amino acid biosynthesis, L-valine biosynthesis

Cofactors or Prosthetic Groups: thiamine diphosphate, FAD [Hill97], FAD [Hill97]

Inhibitors (Unknown Mechanism): glyoxylate [Vinogradov05], sulfometuron methyl [LaRossa84]

Sequence Features

Protein sequence of acetolactate synthase II, large subunit, N-ter fragment (pseudogene) with features indicated

Feature Class Location Attached Group Citations Comment
Amino-Acid-Sites-That-Bind 47  
Inferred by computational analysis[UniProt15]
UniProt: Thiamine pyrophosphate.
Amino-Acid-Sites-That-Bind 149  
Inferred by computational analysis[UniProt15]
UniProt: FAD.
Nucleotide-Phosphate-Binding-Region 251 -> 272 FAD
Inferred by computational analysis[UniProt15]
UniProt: FAD.
Sequence-Conflict 284  
Inferred by curator[Lawther87, UniProt15]
UniProt: (in Ref. 1; AAA24021).
Nucleotide-Phosphate-Binding-Region 294 -> 313 FAD
Inferred by computational analysis[UniProt15]
UniProt: FAD.


Gene Local Context (not to scale -- see Genome Browser for correct scale)

Gene local context diagram

Transcription Units

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram

Notes:


References

Andersen01: Andersen DC, Swartz J, Ryll T, Lin N, Snedecor B (2001). "Metabolic oscillations in an E. coli fermentation." Biotechnol Bioeng 75(2);212-8. PMID: 11536144

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

Barak12: Barak Z, Chipman DM (2012). "Allosteric regulation in Acetohydroxyacid Synthases (AHASs)--different structures and kinetic behavior in isozymes in the same organisms." Arch Biochem Biophys 519(2);167-74. PMID: 22198286

Burns95: Burns DM, Burger MJ, Beacham IR (1995). "Silent genes in bacteria: the previously designated 'cryptic' ilvHI locus of 'Salmonella typhimurium LT2' is active in natural isolates." FEMS Microbiol Lett 131(2);167-72. PMID: 7557326

Dailey86: Dailey FE, Cronan JE (1986). "Acetohydroxy acid synthase I, a required enzyme for isoleucine and valine biosynthesis in Escherichia coli K-12 during growth on acetate as the sole carbon source." J Bacteriol 1986;165(2);453-60. PMID: 3511034

Driver85: Driver RP, Lawther RP (1985). "Physical analysis of deletion mutations in the ilvGEDA operon of Escherichia coli K-12." J Bacteriol 162(2);598-606. PMID: 2985538

Favre76: Favre R, Wiater A, Puppo S, Iaccarino M (1976). "Expression of a valine-resistant acetolactate synthase activity mediated by the ilv O and ilv G genes of Escherichia coli K-12." Mol Gen Genet 143(3);243-52. PMID: 765758

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

Gray81: Gray JE, Patin DW, Calhoun DH (1981). "Identification of the protein products of the rrnC, ilv, rho region of the Escherichia coli K-12 chromosome." Mol Gen Genet 183(3);428-36. PMID: 6460909

Hill97: Hill CM, Pang SS, Duggleby RG (1997). "Purification of Escherichia coli acetohydroxyacid synthase isoenzyme II and reconstitution of active enzyme from its individual pure subunits." Biochem J 327 ( Pt 3);891-8. PMID: 9581571

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

LaRossa84: LaRossa RA, Schloss JV (1984). "The sulfonylurea herbicide sulfometuron methyl is an extremely potent and selective inhibitor of acetolactate synthase in Salmonella typhimurium." J Biol Chem 1984;259(14);8753-7. PMID: 6378902

Lawther81: Lawther RP, Calhoun DH, Adams CW, Hauser CA, Gray J, Hatfield GW (1981). "Molecular basis of valine resistance in Escherichia coli K-12." Proc Natl Acad Sci U S A 78(2);922-5. PMID: 7015336

Lawther82: Lawther RP, Calhoun DH, Gray J, Adams CW, Hauser CA, Hatfield GW (1982). "DNA sequence fine-structure analysis of ilvG (IlvG+) mutations of Escherichia coli K-12." J Bacteriol 149(1);294-8. PMID: 7033211

Lawther87: Lawther RP, Wek RC, Lopes JM, Pereira R, Taillon BE, Hatfield GW (1987). "The complete nucleotide sequence of the ilvGMEDA operon of Escherichia coli K-12." Nucleic Acids Res 1987;15(5);2137-55. PMID: 3550695

Lu87: Lu MF, Umbarger HE (1987). "Effects of deletion and insertion mutations in the ilvM gene of Escherichia coli." J Bacteriol 169(2);600-4. PMID: 3027038

Niu11: Niu X, Liu X, Zhou Y, Niu C, Xi Z, Su XD (2011). "Preliminary X-ray crystallographic studies of the catalytic subunit of Escherichia coli AHAS II with its cofactors." Acta Crystallogr Sect F Struct Biol Cryst Commun 67(Pt 6);659-61. PMID: 21636904

Oh00: Oh MK, Liao JC (2000). "Gene expression profiling by DNA microarrays and metabolic fluxes in Escherichia coli." Biotechnol Prog 16(2);278-86. PMID: 10753455

Parekh97: Parekh BS, Hatfield GW (1997). "Growth rate-related regulation of the ilvGMEDA operon of Escherichia coli K-12 is a consequence of the polar frameshift mutation in the ilvG gene of this strain." J Bacteriol 1997;179(6);2086-8. PMID: 9068661

Reaves11: Reaves ML, Rabinowitz JD (2011). "Characteristic phenotypes associated with ptsN-null mutants in Escherichia coli K-12 are absent in strains with functional ilvG." J Bacteriol 193(18);4576-81. PMID: 21531803

Sameshima89: Sameshima JH, Wek RC, Hatfield GW (1989). "Overlapping transcription and termination of the convergent ilvA and ilvY genes of Escherichia coli." J Biol Chem 1989;264(2);1224-31. PMID: 2642900

Steinmetz10: Steinmetz A, Vyazmensky M, Meyer D, Barak ZE, Golbik R, Chipman DM, Tittmann K (2010). "Valine 375 and phenylalanine 109 confer affinity and specificity for pyruvate as donor substrate in acetohydroxy acid synthase isozyme II from Escherichia coli." Biochemistry 49(25);5188-99. PMID: 20504042

UniProt15: UniProt Consortium (2015). "UniProt version 2015-08 released on 2015-07-22." Database.

Vinogradov05: Vinogradov M, Kaplun A, Vyazmensky M, Engel S, Golbik R, Tittmann K, Uhlemann K, Meshalkina L, Barak Z, Hubner G, Chipman DM (2005). "Monitoring the acetohydroxy acid synthase reaction and related carboligations by circular dichroism spectroscopy." Anal Biochem 342(1);126-33. PMID: 15958189

Vyazmensky09: Vyazmensky M, Zherdev Y, Slutzker A, Belenky I, Kryukov O, Barak Z, Chipman DM (2009). "Interactions between large and small subunits of different acetohydroxyacid synthase isozymes of Escherichia coli." Biochemistry 48(36);8731-7. PMID: 19653643

Vyazmensky11: Vyazmensky M, Steinmetz A, Meyer D, Golbik R, Barak Z, Tittmann K, Chipman DM (2011). "Significant catalytic roles for Glu47 and Gln 110 in all four of the C-C bond-making and -breaking steps of the reactions of acetohydroxyacid synthase II." Biochemistry 50(15);3250-60. PMID: 21370850

Other References Related to Gene Regulation

Adams85: Adams CW, Rosenberg M, Hatfield GW (1985). "Analysis of in vivo RNA transcription products of the ilvGEDA attenuator region of Escherichia coli K12." J Biol Chem 1985;260(14);8538-44. PMID: 2409090

Pagel91: Pagel JM, Hatfield GW (1991). "Integration host factor-mediated expression of the ilvGMEDA operon of Escherichia coli." J Biol Chem 1991;266(3);1985-96. PMID: 1703160

Pagel92: Pagel JM, Winkelman JW, Adams CW, Hatfield GW (1992). "DNA topology-mediated regulation of transcription initiation from the tandem promoters of the ilvGMEDA operon of Escherichia coli." J Mol Biol 1992;224(4);919-35. PMID: 1569580

Parekh96: Parekh BS, Hatfield GW (1996). "Transcriptional activation by protein-induced DNA bending: evidence for a DNA structural transmission model." Proc Natl Acad Sci U S A 1996;93(3);1173-7. PMID: 8577735

Parekh96a: Parekh BS, Sheridan SD, Hatfield GW (1996). "Effects of integration host factor and DNA supercoiling on transcription from the ilvPG promoter of Escherichia coli." J Biol Chem 1996;271(34);20258-64. PMID: 8702758

Rhee96: Rhee KY, Parekh BS, Hatfield GW (1996). "Leucine-responsive regulatory protein-DNA interactions in the leader region of the ilvGMEDA operon of Escherichia coli." J Biol Chem 1996;271(43);26499-507. PMID: 8900118

Subrahmanyam80: Subrahmanyam CS, Noti JD, Umbarger HE (1980). "Regulation of ilvEDA expression occurs upstream of ilvG in Escherichia coli: additional evidence for an ilvGEDA operon." J Bacteriol 144(1);279-90. PMID: 6252193

Tsui88: Tsui P, Freundlich M (1988). "Integration host factor binds specifically to sites in the ilvGMEDA operon in Escherichia coli." J Mol Biol 203(3);817-20. PMID: 3145340


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Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
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