Reviewed, UniProtKB/Swiss-Prot P00892 (ILVG_ECOLI)

Names and origin

Protein names

Recommended name:
    Acetolactate synthase isozyme 2 large subunit
      Short name=AHAS-II
    EC=2.2.1.6
Alternative name(s):
    Acetohydroxy-acid synthase II large subunit
    ALS-II

Gene names

Name:	ilvG
Ordered Locus Names:	b4488
ORF Names:	b3767

Organism

Escherichia coli (strain K12) [Complete proteome] [HAMAP]

Taxonomic identifier

83333 [NCBI]

Taxonomic lineage

Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacteriales › Enterobacteriaceae › Escherichia

Protein attributes

Sequence length	548 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

General annotation (Comments)

Function	Catalyzes the first step in the biosynthesis of branched-chain amino acids.
Catalytic activity	2 pyruvate = 2-acetolactate + CO2.
Cofactor	Binds 1 FAD per subunit. The role of this cofactor is not clear considering that the reaction does not involve redox chemistry. However after removal of the FAD no AHAS activity can be detected (Ref.6), indicating that the cofactor is essential. The large subunit alone does not bind FAD, and FAD is not necessary for association of the subunits. Ref.6 Binds 1 magnesium ion per subunit. Is not necessary for subunit association. Ref.6 Binds 1 thiamine pyrophosphate per subunit. Is not necessary for subunit association. Ref.6
Pathway	Amino-acid biosynthesis; L-isoleucine biosynthesis; L-isoleucine from 2-oxobutanoate: step 1/4. Amino-acid biosynthesis; L-valine biosynthesis; L-valine from pyruvate: step 1/4.
Subunit structure	Tetramer of two large (ilvG) and two small (ilvM) chains. Ref.6
Miscellaneous	E.coli contains genes for 3 AHAS isozymes: ilvBN, ilvGM and ilvIH. In strain K12 only the Val-inhibitable ilvBN and ilvIH are expressed; ilvGM has a defect that disturbs the ilvG reading frame. IlvG (this protein) is Val-resistant and is expressed in K12 strains having what used to be referred to as ilv0 mutations. The ilv02096 mutation (shown here, an insertion of 2 bp, Ref.7) causes a frameshift which restores the open reading frame, permitting the expression of this isozyme.
Sequence similarities	Belongs to the TPP enzyme family.

Ontologies

Keywords
Biological process	Amino-acid biosynthesis Branched-chain amino acid biosynthesis
Ligand	FAD Flavoprotein Magnesium Metal-binding Thiamine pyrophosphate
Molecular function	Transferase
Technical term	Complete proteome Direct protein sequencing
Gene Ontology (GO)
Biological process	branched chain family amino acid biosynthetic process Inferred from electronic annotation. Source: UniProtKB-KW
Molecular function	FAD binding Inferred from electronic annotation. Source: InterPro acetolactate synthase activity Inferred from electronic annotation. Source: EC magnesium ion binding Inferred from electronic annotation. Source: UniProtKB-KW protein binding Inferred from physical interaction. Source: IntAct thiamin pyrophosphate binding Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Binary interactions

With	Entry	#Exp.	IntAct	Notes
galR	P03024	1	EBI-1133701,EBI-556902

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – 548	548	Acetolactate synthase isozyme 2 large subunit		PRO_0000090788
Regions
	Nucleotide binding	251 – 272	22	FAD By similarity
	Nucleotide binding	294 – 313	20	FAD By similarity
	Region	377 – 457	81	Thiamine pyrophosphate binding
Sites
	Metal binding	428	1	Magnesium By similarity
	Metal binding	455	1	Magnesium By similarity
	Binding site	47	1	Thiamine pyrophosphate By similarity
	Binding site	149	1	FAD By similarity
Experimental info
	Sequence conflict	284	1	F → S in AAA24021. Ref.1

Sequences

	Sequence		Length	Mass (Da)
	P00892-1 [UniParc]. Last modified July 19, 2003. Version 3. Checksum: A002C07DAA6476DA	FASTA	548	59,285
	10 20 30 40 50 60 MNGAQWVVHA LRAQGVNTVF GYPGGAIMPV YDALYDGGVE HLLCRHEQGA AMAAIGYARA 70 80 90 100 110 120 TGKTGVCIAT SGPGATNLIT GLADALLDSI PVVAITGQVS APFIGTDAFQ EVDVLGLSLA 130 140 150 160 170 180 CTKHSFLVQS LEELPRIMAE AFDVACSGRP GPVLVDIPKD IQLASGDLEP WFTTVENEVT 190 200 210 220 230 240 FPHAEVEQAR QMLAKAQKPM LYVGGGVGMA QAVPALREFL AATKMPATCT LKGLGAVEAD 250 260 270 280 290 300 YPYYLGMLGM HGTKAANFAV QECDLLIAVG ARFDDRVTGK LNTFAPHASV IHMDIDPAEM 310 320 330 340 350 360 NKLRQAHVAL QGDLNALLPA LQQPLNQYDW QQHCAQLRDE HSWRYDHPGD AIYAPLLLKQ 370 380 390 400 410 420 LSDRKPADCV VTTDVGQHQM WAAQHIAHTR PENFITSSGL GTMGFGLPAA VGAQVARPND 430 440 450 460 470 480 TVVCISGDGS FMMNVQELGT VKRKQLPLKI VLLDNQRLGM VRQWQQLFFQ ERYSETTLTD 490 500 510 520 530 540 NPDFLMLASA FGIHGQHITR KDQVEAALDT MLNSDGPYLL HVSIDELENV WPLVPPGASN SEMLEKLS

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"The complete nucleotide sequence of the ilvGMEDA operon of Escherichia coli K-12." Lawther R.P., Wek R.C., Lopes J.M., Pereira R., Taillon B.E., Hatfield G.W. Nucleic Acids Res. 15:2137-2155(1987) [PubMed: 3550695] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA]. Strain: K12.
[2]	"Analysis of the Escherichia coli genome: DNA sequence of the region from 84.5 to 86.5 minutes." Daniels D.L., Plunkett G. III, Burland V.D., Blattner F.R. Science 257:771-778(1992) [PubMed: 1379743] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / MG1655 / ATCC 47076.
[3]	"The complete genome sequence of Escherichia coli K-12." Blattner F.R., Plunkett G. III, Bloch C.A., Perna N.T., Burland V., Riley M., Collado-Vides J., Glasner J.D., Rode C.K., Mayhew G.F., Gregor J., Davis N.W., Kirkpatrick H.A., Goeden M.A., Rose D.J., Mau B., Shao Y. Science 277:1453-1474(1997) [PubMed: 9278503] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: K12 / MG1655 / ATCC 47076.
[4]	"Sequence and transcriptional activity of the Escherichia coli K-12 chromosome region between rrnC and ilvGMEDA." Coppola G., Huang F., Riley J., Cox J.L., Hantzopoulos P., Zhou L.-B., Calhoun D.H. Gene 97:21-27(1991) [PubMed: 1995430] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 1-402. Strain: K12.
[5]	"Multivalent translational control of transcription termination at attenuator of ilvGEDA operon of Escherichia coli K-12." Lawther R.P., Hatfield G.W. Proc. Natl. Acad. Sci. U.S.A. 77:1862-1866(1980) [PubMed: 6154938] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 1-14. Strain: K12.
[6]	"Purification of Escherichia coli acetohydroxyacid synthase isoenzyme II and reconstitution of active enzyme from its individual pure subunits." Hill C.M., Pang S.S., Duggleby R.G. Biochem. J. 327:891-898(1997) [PubMed: 9581571] [Abstract] Cited for: PROTEIN SEQUENCE OF 1-3, SUBUNIT, COFACTOR, REMOVAL OF FAD COFACTOR. Strain: K12 / mutant ILV02096.
[7]	"Molecular basis of valine resistance in Escherichia coli K-12." Lawther R.P., Calhoun D.H., Adams C.W., Hauser C.A., Gray J., Hatfield G.W. Proc. Natl. Acad. Sci. U.S.A. 78:922-925(1981) [PubMed: 7015336] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 28-548, IDENTIFICATION OF FRAMESHIFT THAT RESTORES THE READING FRAME. Strain: K12 / mutant ILV02096.
[8]	"Branched-chain amino acid aminotransferase of Escherichia coli: nucleotide sequence of the ilvE gene and the deduced amino acid sequence." Kuramitsu S., Ogawa T., Ogawa H., Kagamiyama H. J. Biochem. 97:993-999(1985) [PubMed: 3897211] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 543-548. Strain: K12.

Cross-references

Sequence databases
EMBLGenBankDDBJ	M32253 Genomic DNA. Translation: AAA24021.1. X04890 Genomic DNA. Translation: CAA28573.1. M87049 Genomic DNA. Translation: AAA67571.1. Sequence problems. U00096 Genomic DNA. No translation available. M37337 Genomic DNA. Translation: AAA24608.1. V00289 Genomic DNA. Translation: CAA23556.1. M10313 Genomic DNA. Translation: AAB59050.1. V00290 Genomic DNA. Translation: CAA23558.1. Sequence problems. X02413 Genomic DNA. Translation: CAA26260.1.
PIR	YCEC. A26570.
3D structure databases
HSSP	HSSP built from PDB template 1N0H based on UniProtKB P07342.
ModBase	Search...
Protein-protein interaction databases
DIP	DIP:10023N.
IntAct	P00892. 1 interaction.
Genome annotation databases
GenomeReviews	Gene locus b4488 in contig U00096_GR.
KEGG	eco:b4488.
Organism-specific databases
EchoBASE	EB0493.
EcoGene	EG10498. ilvG.
CMR	Search...
Phylogenomic databases
HOGENOM	P00892.
OMA	P00892. HSWRYDH.
Enzyme and pathway databases
BioCyc	EcoCyc:G8221-MON. EcoCyc:LARGEILVG-MON. MetaCyc:G8221-MON. MetaCyc:LARGEILVG-MON.
Family and domain databases
InterPro	IPR012846. Acetolactate_synth_lsu. IPR000399. TPP_bd_CS. IPR012001. TPP_bd_enzyme_N. IPR011766. TPP_enzyme_bd_C. IPR012000. TPP_enzyme_M. [Graphical view]
Pfam	PF02775. TPP_enzyme_C. 1 hit. PF00205. TPP_enzyme_M. 1 hit. PF02776. TPP_enzyme_N. 1 hit. [Graphical view]
TIGRFAMs	TIGR00118. acolac_lg. 1 hit.
PROSITE	PS00187. TPP_ENZYMES. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

ILVG_ECOLI

Accession

Primary (citable) accession number: P00892
Secondary accession number(s): P76749

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	July 19, 2003
Last modified:	June 16, 2009
This is version 101 of the entry and version 3 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

HAMAP (High-quality Automated and Manual Annotation of microbial Proteomes)