L-valine biosynthesis

MetaCyc:VALSYN-PWY

L-valine biosynthesis condenses pyruvate to (2S)-2-acetolactate, reduces and rearranges it to (2R)-2,3-dihydroxy-3-methylbutanoate, dehydrates that intermediate to 3-methyl-2-oxobutanoate, and transaminates it to L-valine.

Pathway type

amino acid biosynthesis

Organism scope

Escherichia coli NCBITaxon:562

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Pathway network

33 nodes · 44 asserted directed edges

Arrows show recorded subject → object relationships, not necessarily metabolic flow. Select a node for details or an arrow for evidence. Scroll, zoom or find a node to explore.

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Chemical / cofactor
Protein / complex
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Cell / process context
Solid arrow: mechanistic relation
Dashed arrow: membership, location or cofactor relation

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Components and activities

Declared biological components and source reaction directions
Node	Kind or role	Source direction
Escherichia coli `NCBITaxon:562`	taxon
acetolactate synthase `EC:2.2.1.6`	molecular activity
ketol-acid reductoisomerase (NADP(+)) `EC:1.1.1.86`	molecular activity
dihydroxy-acid dehydratase `EC:4.2.1.9`	molecular activity
branched-chain-amino-acid transaminase `EC:2.6.1.42`	molecular activity
pyruvate `CHEBI:15361`	small molecule
H+ `CHEBI:15378`	small molecule
(2S)-2-acetolactate `CHEBI:58476`	small molecule
CO2 `CHEBI:16526`	small molecule
NADPH `CHEBI:57783`	small molecule
(2R)-2,3-dihydroxy-3-methylbutanoate `CHEBI:49072`	small molecule
NADP(+) `CHEBI:58349`	small molecule
3-methyl-2-oxobutanoate `CHEBI:11851`	small molecule
H2O `CHEBI:15377`	small molecule
L-glutamate `CHEBI:29985`	small molecule
L-valine `CHEBI:57762`	small molecule
2-oxoglutarate `CHEBI:16810`	small molecule
Acetolactate synthase isozyme 3 large subunit `UniProtKB:P00893`	protein
magnesium(2+) `CHEBI:18420`	cofactor
thiamine(1+) diphosphate(3-) `CHEBI:58937`	cofactor
Acetolactate synthase isozyme 3 small subunit `UniProtKB:P00894`	protein
Dihydroxy-acid dehydratase `UniProtKB:P05791`	protein
iron-sulfur cluster `CHEBI:30408`	cofactor
Ketol-acid reductoisomerase (NADP(+)) `UniProtKB:P05793`	protein
cytoplasm `GO:0005737`	cellular component
Acetolactate synthase isozyme 1 large subunit `UniProtKB:P08142`	protein
Branched-chain-amino-acid aminotransferase `UniProtKB:P0AB80`	protein
pyridoxal 5'-phosphate(2-) `CHEBI:597326`	cofactor
Acetolactate synthase isozyme 1 small subunit `UniProtKB:P0ADF8`	protein
Acetolactate synthase isozyme 2 small subunit `UniProtKB:P0ADG1`	protein
acetolactate synthase reaction `RHEA:25250`	reaction	left to right
acetohydroxy acid isomeroreductase reaction `RHEA:22070`	reaction	right to left
dihydroxy-acid dehydratase reaction `RHEA:24810`	reaction	left to right
L-valine aminotransferase reaction `RHEA:24815`	reaction	right to left

Mechanistic edges

Mechanistic edges and their cited evidence
Subject	Predicate and description	Object	Evidence
pyruvate `CHEBI:15361`	consumes	acetolactate synthase reaction `RHEA:25250`	RHEA:25250 Source assertion: Rhea lists CHEBI:15361 on the substrates side of RHEA:25250 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/25250']/rh:substrates; rh:contains/rh:compound/rh:accession`
H+ `CHEBI:15378`	consumes	acetolactate synthase reaction `RHEA:25250`	RHEA:25250 Source assertion: Rhea lists CHEBI:15378 on the substrates side of RHEA:25250 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/25250']/rh:substrates; rh:contains/rh:compound/rh:accession`
acetolactate synthase reaction `RHEA:25250`	produces	CO2 `CHEBI:16526`	RHEA:25250 Source assertion: Rhea lists CHEBI:16526 on the products side of RHEA:25250 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/25250']/rh:products; rh:contains/rh:compound/rh:accession`
acetolactate synthase reaction `RHEA:25250`	produces	(2S)-2-acetolactate `CHEBI:58476`	RHEA:25250 Source assertion: Rhea lists CHEBI:58476 on the products side of RHEA:25250 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/25250']/rh:products; rh:contains/rh:compound/rh:accession`
H+ `CHEBI:15378`	consumes	acetohydroxy acid isomeroreductase reaction `RHEA:22070`	RHEA:22070 Source assertion: Rhea lists CHEBI:15378 on the substrates side of RHEA:22070 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/22070']/rh:substrates; rh:contains/rh:compound/rh:accession`
NADPH `CHEBI:57783`	consumes	acetohydroxy acid isomeroreductase reaction `RHEA:22070`	RHEA:22070 Source assertion: Rhea lists CHEBI:57783 on the substrates side of RHEA:22070 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/22070']/rh:substrates; rh:contains/rh:compound/rh:accession`
(2S)-2-acetolactate `CHEBI:58476`	consumes	acetohydroxy acid isomeroreductase reaction `RHEA:22070`	RHEA:22070 Source assertion: Rhea lists CHEBI:58476 on the substrates side of RHEA:22070 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/22070']/rh:substrates; rh:contains/rh:compound/rh:accession`
acetohydroxy acid isomeroreductase reaction `RHEA:22070`	produces	(2R)-2,3-dihydroxy-3-methylbutanoate `CHEBI:49072`	RHEA:22070 Source assertion: Rhea lists CHEBI:49072 on the products side of RHEA:22070 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/22070']/rh:products; rh:contains/rh:compound/rh:accession`
acetohydroxy acid isomeroreductase reaction `RHEA:22070`	produces	NADP(+) `CHEBI:58349`	RHEA:22070 Source assertion: Rhea lists CHEBI:58349 on the products side of RHEA:22070 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/22070']/rh:products; rh:contains/rh:compound/rh:accession`
(2R)-2,3-dihydroxy-3-methylbutanoate `CHEBI:49072`	consumes	dihydroxy-acid dehydratase reaction `RHEA:24810`	RHEA:24810 Source assertion: Rhea lists CHEBI:49072 on the substrates side of RHEA:24810 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/24810']/rh:substrates; rh:contains/rh:compound/rh:accession`
dihydroxy-acid dehydratase reaction `RHEA:24810`	produces	3-methyl-2-oxobutanoate `CHEBI:11851`	RHEA:24810 Source assertion: Rhea lists CHEBI:11851 on the products side of RHEA:24810 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/24810']/rh:products; rh:contains/rh:compound/rh:accession`
dihydroxy-acid dehydratase reaction `RHEA:24810`	produces	H2O `CHEBI:15377`	RHEA:24810 Source assertion: Rhea lists CHEBI:15377 on the products side of RHEA:24810 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/24810']/rh:products; rh:contains/rh:compound/rh:accession`
3-methyl-2-oxobutanoate `CHEBI:11851`	consumes	L-valine aminotransferase reaction `RHEA:24815`	RHEA:24815 Source assertion: Rhea lists CHEBI:11851 on the substrates side of RHEA:24815 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/24815']/rh:substrates; rh:contains/rh:compound/rh:accession`
L-glutamate `CHEBI:29985`	consumes	L-valine aminotransferase reaction `RHEA:24815`	RHEA:24815 Source assertion: Rhea lists CHEBI:29985 on the substrates side of RHEA:24815 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/24815']/rh:substrates; rh:contains/rh:compound/rh:accession`
L-valine aminotransferase reaction `RHEA:24815`	produces	2-oxoglutarate `CHEBI:16810`	RHEA:24815 Source assertion: Rhea lists CHEBI:16810 on the products side of RHEA:24815 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/24815']/rh:products; rh:contains/rh:compound/rh:accession`
L-valine aminotransferase reaction `RHEA:24815`	produces	L-valine `CHEBI:57762`	RHEA:24815 Source assertion: Rhea lists CHEBI:57762 on the products side of RHEA:24815 in this directed reaction. Source location `rdf:Description[@rdf:about='http://rdf.rhea-db.org/24815']/rh:products; rh:contains/rh:compound/rh:accession`
acetolactate synthase `EC:2.2.1.6`	catalyzes	acetolactate synthase reaction `RHEA:25250`	RHEA:25249 Source assertion: Rhea associates EC:2.2.1.6 with the reaction family containing RHEA:25250. Source location `rh:ec` PMID:3301814 Physiological implications of the specificity of acetohydroxy acid synthase isozymes of enteric bacteria. Source location `PubMed ArticleTitle`
ketol-acid reductoisomerase (NADP(+)) `EC:1.1.1.86`	catalyzes	acetohydroxy acid isomeroreductase reaction `RHEA:22070`	RHEA:22068 Source assertion: Rhea associates EC:1.1.1.86 with the reaction family containing RHEA:22070. Source location `rh:ec` PMID:27136273 Ketol-acid reductoisomerase (KARI) is a Mg(2+) -dependent enzyme in the branched-chain amino acid biosynthesis pathway. Source location `PubMed Abstract`
dihydroxy-acid dehydratase `EC:4.2.1.9`	catalyzes	dihydroxy-acid dehydratase reaction `RHEA:24810`	RHEA:24809 Source assertion: Rhea associates EC:4.2.1.9 with the reaction family containing RHEA:24810. Source location `rh:ec` PMID:13727223 Dihydroxy acid dehydrase: an enzyme involved in the biosynthesis of isoleucine and valine. Source location `PubMed ArticleTitle`
branched-chain-amino-acid transaminase `EC:2.6.1.42`	catalyzes	L-valine aminotransferase reaction `RHEA:24815`	RHEA:24813 Source assertion: Rhea associates EC:2.6.1.42 with the reaction family containing RHEA:24815. Source location `rh:ec` PMID:378964 Transaminase B from Escherichia coli: quaternary structure, amino-terminal sequence, substrate specificity, and absence of a separate valine-alpha-ketoglutarate activity. Source location `PubMed ArticleTitle`
acetohydroxy acid isomeroreductase reaction `RHEA:22070`	precedes	dihydroxy-acid dehydratase reaction `RHEA:24810`	MetaCyc:VALSYN-PWY Source assertion: MetaCyc pathway ordering places RHEA:22070 before RHEA:24810 in this pathway. Shared intermediate: CHEBI:49072. Source location `Pathway/reaction-ordering and reaction-layout; Rhea-to-MetaCyc cross-references`
dihydroxy-acid dehydratase reaction `RHEA:24810`	precedes	L-valine aminotransferase reaction `RHEA:24815`	MetaCyc:VALSYN-PWY Source assertion: MetaCyc pathway ordering places RHEA:24810 before RHEA:24815 in this pathway. Shared intermediate: CHEBI:11851. Source location `Pathway/reaction-ordering and reaction-layout; Rhea-to-MetaCyc cross-references`
acetolactate synthase reaction `RHEA:25250`	precedes	acetohydroxy acid isomeroreductase reaction `RHEA:22070`	MetaCyc:VALSYN-PWY Source assertion: MetaCyc pathway ordering places RHEA:25250 before RHEA:22070 in this pathway. Shared intermediate: CHEBI:58476. Source location `Pathway/reaction-ordering and reaction-layout; Rhea-to-MetaCyc cross-references`
Acetolactate synthase isozyme 3 large subunit `UniProtKB:P00893`	enables	acetolactate synthase reaction `RHEA:25250`	UniProtKB:P00893 Source assertion: UniProt annotates UniProtKB:P00893 with catalytic activity for the reaction family of RHEA:25250. Annotation evidence: curated source annotation; organism taxon: NCBITaxon:83333. Source location `comments[commentType='CATALYTIC ACTIVITY'].reaction.reactionCrossReferences`
L-valine `CHEBI:57762`	inhibits	Acetolactate synthase isozyme 3 large subunit `UniProtKB:P00893`	UniProtKB:P00893 Source assertion: UniProt activity-regulation annotation: Sensitive to valine inhibition Source location `comments[commentType='ACTIVITY REGULATION'].texts`
Acetolactate synthase isozyme 3 large subunit `UniProtKB:P00893`	has_cofactor	magnesium(2+) `CHEBI:18420`	UniProtKB:P00893 Source assertion: UniProt lists CHEBI:18420 as a cofactor of UniProtKB:P00893 (evidence: ECO:0000250). Binds 1 Mg(2+) ion per subunit. Source location `comments[commentType='COFACTOR'].cofactors and note`
Acetolactate synthase isozyme 3 large subunit `UniProtKB:P00893`	has_cofactor	thiamine(1+) diphosphate(3-) `CHEBI:58937`	UniProtKB:P00893 Source assertion: UniProt lists CHEBI:58937 as a cofactor of UniProtKB:P00893 (evidence: ECO:0000250). Binds 1 thiamine pyrophosphate per subunit. Source location `comments[commentType='COFACTOR'].cofactors and note`
Acetolactate synthase isozyme 3 small subunit `UniProtKB:P00894`	enables	acetolactate synthase reaction `RHEA:25250`	UniProtKB:P00894 Source assertion: UniProt annotates UniProtKB:P00894 with catalytic activity for the reaction family of RHEA:25250. Annotation evidence: curated source annotation; organism taxon: NCBITaxon:83333. Source location `comments[commentType='CATALYTIC ACTIVITY'].reaction.reactionCrossReferences`
L-valine `CHEBI:57762`	inhibits	Acetolactate synthase isozyme 3 small subunit `UniProtKB:P00894`	UniProtKB:P00894 Source assertion: UniProt activity-regulation annotation: Sensitive to valine inhibition Source location `comments[commentType='ACTIVITY REGULATION'].texts`
Dihydroxy-acid dehydratase `UniProtKB:P05791`	enables	dihydroxy-acid dehydratase reaction `RHEA:24810`	UniProtKB:P05791 Source assertion: UniProt annotates UniProtKB:P05791 with catalytic activity for the reaction family of RHEA:24810. Annotation evidence: ECO:0000269; organism taxon: NCBITaxon:83333. Source location `comments[commentType='CATALYTIC ACTIVITY'].reaction.reactionCrossReferences`
Dihydroxy-acid dehydratase `UniProtKB:P05791`	has_cofactor	iron-sulfur cluster `CHEBI:30408`	UniProtKB:P05791 Source assertion: UniProt lists CHEBI:30408 as a cofactor of UniProtKB:P05791 (evidence: ECO:0000255). Cluster nuclearity is left unspecified: the current UniProt annotation infers [2Fe-2S], while its caution cites older E. coli [4Fe-4S] evidence and a later M. tuberculosis result. Source location `comments[commentType='COFACTOR'].cofactors and note`
Dihydroxy-acid dehydratase `UniProtKB:P05791`	has_cofactor	magnesium(2+) `CHEBI:18420`	UniProtKB:P05791 Source assertion: UniProt lists CHEBI:18420 as a cofactor of UniProtKB:P05791 (evidence: ECO:0000255). Source location `comments[commentType='COFACTOR'].cofactors and note`
Ketol-acid reductoisomerase (NADP(+)) `UniProtKB:P05793`	enables	acetohydroxy acid isomeroreductase reaction `RHEA:22070`	UniProtKB:P05793 Source assertion: UniProt annotates UniProtKB:P05793 with catalytic activity for the reaction family of RHEA:22070. Annotation evidence: ECO:0000255, ECO:0000269; organism taxon: NCBITaxon:83333. Source location `comments[commentType='CATALYTIC ACTIVITY'].reaction.reactionCrossReferences`
Ketol-acid reductoisomerase (NADP(+)) `UniProtKB:P05793`	located_in	cytoplasm `GO:0005737`	UniProtKB:P05793 Source assertion: UniProt locates UniProtKB:P05793 in Cytoplasm (SL-0086, mapped by UniProt to GO:0005737). Annotation evidence: ECO:0000305. Source location `comments[commentType='SUBCELLULAR LOCATION'].subcellularLocations; UniProt location vocabulary GO mapping`
Ketol-acid reductoisomerase (NADP(+)) `UniProtKB:P05793`	has_cofactor	magnesium(2+) `CHEBI:18420`	UniProtKB:P05793 Source assertion: UniProt lists CHEBI:18420 as a cofactor of UniProtKB:P05793 (evidence: ECO:0000255, ECO:0000269). Binds 2 magnesium ions per subunit. Source location `comments[commentType='COFACTOR'].cofactors and note`
Acetolactate synthase isozyme 1 large subunit `UniProtKB:P08142`	enables	acetolactate synthase reaction `RHEA:25250`	UniProtKB:P08142 Source assertion: UniProt annotates UniProtKB:P08142 with catalytic activity for the reaction family of RHEA:25250. Annotation evidence: curated source annotation; organism taxon: NCBITaxon:83333. Source location `comments[commentType='CATALYTIC ACTIVITY'].reaction.reactionCrossReferences`
Acetolactate synthase isozyme 1 large subunit `UniProtKB:P08142`	has_cofactor	magnesium(2+) `CHEBI:18420`	UniProtKB:P08142 Source assertion: UniProt lists CHEBI:18420 as a cofactor of UniProtKB:P08142 (evidence: ECO:0000250). Binds 1 Mg(2+) ion per subunit. Source location `comments[commentType='COFACTOR'].cofactors and note`
Acetolactate synthase isozyme 1 large subunit `UniProtKB:P08142`	has_cofactor	thiamine(1+) diphosphate(3-) `CHEBI:58937`	UniProtKB:P08142 Source assertion: UniProt lists CHEBI:58937 as a cofactor of UniProtKB:P08142 (evidence: ECO:0000250). Binds 1 thiamine pyrophosphate per subunit. Source location `comments[commentType='COFACTOR'].cofactors and note`
Branched-chain-amino-acid aminotransferase `UniProtKB:P0AB80`	enables	L-valine aminotransferase reaction `RHEA:24815`	UniProtKB:P0AB80 Source assertion: UniProt annotates UniProtKB:P0AB80 with catalytic activity for the reaction family of RHEA:24815. Annotation evidence: curated source annotation; organism taxon: NCBITaxon:83333. Source location `comments[commentType='CATALYTIC ACTIVITY'].reaction.reactionCrossReferences`
Branched-chain-amino-acid aminotransferase `UniProtKB:P0AB80`	has_cofactor	pyridoxal 5'-phosphate(2-) `CHEBI:597326`	UniProtKB:P0AB80 Source assertion: UniProt lists CHEBI:597326 as a cofactor of UniProtKB:P0AB80 (evidence: curated annotation). Source location `comments[commentType='COFACTOR'].cofactors and note`
Acetolactate synthase isozyme 1 small subunit `UniProtKB:P0ADF8`	enables	acetolactate synthase reaction `RHEA:25250`	UniProtKB:P0ADF8 Source assertion: UniProt annotates UniProtKB:P0ADF8 with catalytic activity for the reaction family of RHEA:25250. Annotation evidence: curated source annotation; organism taxon: NCBITaxon:83333. Source location `comments[commentType='CATALYTIC ACTIVITY'].reaction.reactionCrossReferences`
Acetolactate synthase isozyme 2 small subunit `UniProtKB:P0ADG1`	enables	acetolactate synthase reaction `RHEA:25250`	UniProtKB:P0ADG1 Source assertion: UniProt annotates UniProtKB:P0ADG1 with catalytic activity for the reaction family of RHEA:25250. Annotation evidence: curated source annotation; organism taxon: NCBITaxon:83333. Source location `comments[commentType='CATALYTIC ACTIVITY'].reaction.reactionCrossReferences`
Acetolactate synthase isozyme 2 small subunit `UniProtKB:P0ADG1`	has_cofactor	magnesium(2+) `CHEBI:18420`	UniProtKB:P0ADG1 Source assertion: UniProt lists CHEBI:18420 as a cofactor of UniProtKB:P0ADG1 (evidence: ECO:0000250). Binds 1 Mg(2+) ion per subunit. Source location `comments[commentType='COFACTOR'].cofactors and note`
Acetolactate synthase isozyme 2 small subunit `UniProtKB:P0ADG1`	has_cofactor	thiamine(1+) diphosphate(3-) `CHEBI:58937`	UniProtKB:P0ADG1 Source assertion: UniProt lists CHEBI:58937 as a cofactor of UniProtKB:P0ADG1 (evidence: ECO:0000250). Binds 1 thiamine pyrophosphate per subunit. Source location `comments[commentType='COFACTOR'].cofactors and note`

References

MetaCyc:VALSYN-PWY MetaCyc L-valine biosynthesis pathway (source version: 22.5)
RHEA:25249 Rhea acetolactate synthase reaction (source version: 139)
RHEA:25250 Rhea acetolactate synthase direction (source version: 139)
RHEA:22068 Rhea acetohydroxy acid isomeroreductase reaction (source version: 139)
RHEA:22070 Rhea biosynthetic acetohydroxy acid isomeroreductase direction (source version: 139)
RHEA:24809 Rhea dihydroxy-acid dehydratase reaction (source version: 139)
RHEA:24810 Rhea dihydroxy-acid-to-3-methyl-2-oxobutanoate direction (source version: 139)
RHEA:24813 Rhea branched-chain-amino-acid transaminase reaction (source version: 139)
RHEA:24815 Rhea biosynthetic L-valine transaminase direction (source version: 139)
PMID:3301814 Barak et al., Journal of Bacteriology, 1987
PMID:27136273 Tadrowski et al., Chemistry - A European Journal, 2016
PMID:13727223 Myers, Journal of Biological Chemistry, 1961
PMID:378964 Lee-Peng et al., Journal of Bacteriology, 1979
UniProtKB:P00893 UniProtKB:P00893 authority record (source version: 2026_03)
UniProtKB:P00894 UniProtKB:P00894 authority record (source version: 2026_03)
UniProtKB:P05791 UniProtKB:P05791 authority record (source version: 2026_03)
UniProtKB:P05793 UniProtKB:P05793 authority record (source version: 2026_03)
UniProtKB:P08142 UniProtKB:P08142 authority record (source version: 2026_03)
UniProtKB:P0AB80 UniProtKB:P0AB80 authority record (source version: 2026_03)
UniProtKB:P0ADF8 UniProtKB:P0ADF8 authority record (source version: 2026_03)
UniProtKB:P0ADG1 UniProtKB:P0ADG1 authority record (source version: 2026_03)

Curation history

2026-10-05T06:25:52Z codex
- EDIT — Review causal chemistry and add sourced molecular context
  Reviewed the entire record against MetaCyc 22.5 native pathway XML (including nested pathways), Rhea 139 explicit sides and directions, ENZYME 02-Sep-2026, PubMed records, and reviewed UniProt 2026_03 annotations within the record's taxon scope. Replaced generated structured-source quotations with source_assertion and source_locator. Typed molecular activities and participants. Reaction count 4 to 4; 0 directed-ID corrections; 8 protein annotations, 10 cofactor annotations and 1 sourced locations. All Rhea reaction substrate/product sets checked against independent Rhea authority; native pathway leaf coverage and source exceptions recorded in reports/causal_graph_review/metacyc-review.json. Full source URLs, versions and byte hashes are in metacyc-sources.json. All 50 MetaCyc records passed native schema validation; six targeted chemistry/evidence regression tests passed. Missing protein or cofactor annotations are not treated as biological absence; qualifications and exclusions are preserved in the ledger. Cluster nuclearity is left unspecified: the current UniProt annotation infers [2Fe-2S], while its caution cites older E. coli [4Fe-4S] evidence and a later M. tuberculosis result. Excluded repaired ilvG frameshift mutant; the ordinary K12 gene is disrupted.
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