ID   ILVI_BUCSC              Reviewed;         574 AA.
AC   Q9RQ65;
DT   25-NOV-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-2000, sequence version 1.
DT   03-AUG-2022, entry version 84.
DE   RecName: Full=Acetolactate synthase large subunit;
DE            Short=AHAS;
DE            EC=2.2.1.6;
DE   AltName: Full=Acetohydroxy-acid synthase large subunit;
DE            Short=ALS;
GN   Name=ilvI;
OS   Buchnera aphidicola subsp. Schlechtendalia chinensis.
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Erwiniaceae; Buchnera.
OX   NCBI_TaxID=118110;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=10555290; DOI=10.1093/oxfordjournals.molbev.a026071;
RA   Clark M.A., Moran N.A., Baumann P.;
RT   "Sequence evolution in bacterial endosymbionts having extreme base
RT   compositions.";
RL   Mol. Biol. Evol. 16:1586-1598(1999).
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=H(+) + 2 pyruvate = (2S)-2-acetolactate + CO2;
CC         Xref=Rhea:RHEA:25249, ChEBI:CHEBI:15361, ChEBI:CHEBI:15378,
CC         ChEBI:CHEBI:16526, ChEBI:CHEBI:58476; EC=2.2.1.6;
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000250};
CC       Note=Binds 1 Mg(2+) ion per subunit. {ECO:0000250};
CC   -!- COFACTOR:
CC       Name=thiamine diphosphate; Xref=ChEBI:CHEBI:58937;
CC         Evidence={ECO:0000250};
CC       Note=Binds 1 thiamine pyrophosphate per subunit. {ECO:0000250};
CC   -!- PATHWAY: Amino-acid biosynthesis; L-isoleucine biosynthesis; L-
CC       isoleucine from 2-oxobutanoate: step 1/4.
CC   -!- PATHWAY: Amino-acid biosynthesis; L-valine biosynthesis; L-valine from
CC       pyruvate: step 1/4.
CC   -!- SUBUNIT: Dimer of large and small chains. {ECO:0000250}.
CC   -!- MISCELLANEOUS: Contains 1 molecule of FAD per monomer. The role of this
CC       cofactor is not clear considering that the reaction does not involve
CC       redox chemistry (By similarity). {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the TPP enzyme family. {ECO:0000305}.
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DR   EMBL; AF129502; AAF13791.1; -; Genomic_DNA.
DR   RefSeq; WP_075474080.1; NZ_CP011299.1.
DR   AlphaFoldDB; Q9RQ65; -.
DR   SMR; Q9RQ65; -.
DR   STRING; 118110.XW81_01055; -.
DR   OMA; CFGTSGP; -.
DR   OrthoDB; 391134at2; -.
DR   UniPathway; UPA00047; UER00055.
DR   UniPathway; UPA00049; UER00059.
DR   GO; GO:0003984; F:acetolactate synthase activity; IEA:UniProtKB-EC.
DR   GO; GO:0050660; F:flavin adenine dinucleotide binding; IEA:InterPro.
DR   GO; GO:0000287; F:magnesium ion binding; IEA:InterPro.
DR   GO; GO:0030976; F:thiamine pyrophosphate binding; IEA:InterPro.
DR   GO; GO:0009097; P:isoleucine biosynthetic process; IEA:UniProtKB-UniPathway.
DR   GO; GO:0009099; P:valine biosynthetic process; IEA:UniProtKB-UniPathway.
DR   CDD; cd02015; TPP_AHAS; 1.
DR   InterPro; IPR012846; Acetolactate_synth_lsu.
DR   InterPro; IPR039368; AHAS_TPP.
DR   InterPro; IPR029035; DHS-like_NAD/FAD-binding_dom.
DR   InterPro; IPR029061; THDP-binding.
DR   InterPro; IPR012000; Thiamin_PyroP_enz_cen_dom.
DR   InterPro; IPR012001; Thiamin_PyroP_enz_TPP-bd_dom.
DR   InterPro; IPR000399; TPP-bd_CS.
DR   InterPro; IPR045229; TPP_enz.
DR   InterPro; IPR011766; TPP_enzyme-bd_C.
DR   PANTHER; PTHR18968; PTHR18968; 1.
DR   Pfam; PF02775; TPP_enzyme_C; 1.
DR   Pfam; PF00205; TPP_enzyme_M; 1.
DR   Pfam; PF02776; TPP_enzyme_N; 1.
DR   SUPFAM; SSF52467; SSF52467; 1.
DR   SUPFAM; SSF52518; SSF52518; 2.
DR   TIGRFAMs; TIGR00118; acolac_lg; 1.
DR   PROSITE; PS00187; TPP_ENZYMES; 1.
PE   3: Inferred from homology;
KW   Amino-acid biosynthesis; Branched-chain amino acid biosynthesis; FAD;
KW   Flavoprotein; Magnesium; Metal-binding; Thiamine pyrophosphate;
KW   Transferase.
FT   CHAIN           1..574
FT                   /note="Acetolactate synthase large subunit"
FT                   /id="PRO_0000090794"
FT   REGION          397..477
FT                   /note="Thiamine pyrophosphate binding"
FT   BINDING         51
FT                   /ligand="thiamine diphosphate"
FT                   /ligand_id="ChEBI:CHEBI:58937"
FT                   /evidence="ECO:0000250"
FT   BINDING         153
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
FT   BINDING         261..282
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
FT   BINDING         304..323
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
FT   BINDING         448
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000250"
FT   BINDING         475
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   574 AA;  63740 MW;  AE18D612C8CD32BD CRC64;
     MEMLSGSEMI IQSLIDQGIK YIFGYPGGAV LDIYDSLKST KKIKHILVRH EQGATHMADG
     YARATGKIGV VLVTSGPGAT NSITGIATAY MDSIPIVVIS GQVSSSLIGY DAFQECDMIG
     ISRPIVKHSF LVKKTEDIPI TFKKAFWLAS SGRPGPIVID LPKDILNSYN KKPYIWPIEV
     NIRSYNPITK GHSRQIKKAI DILKLSKQPV IYAGGGVISA NCHNELKELA EKLNIPVTTS
     LMALGAFPGN HPQNLQMLGM HGTYEANMAM HYADVILAIG VRFDDRTTNN VKKYCPNATI
     IHIDIDPTSI SKTITAHIPI VGNAKNVLQQ ILVFINSNMF VKEFYCLKKW WIKIQSWKNK
     NSLNFDTNSD NIKPQSVIKT IWKLTKGKAF ITSDVGQHQM FAALYYSFQK PRRWINSGGL
     GTMGFGLPAA LGVKLAFPNE TVICVTGDGS IQMNIQELST AMQYELPILI LNLNNKSLGM
     VKQWQDIIYS GRHSHSYMKS LPNFIKLAES YGHSGISINT PKELEKKLQL ALEKLQNGHL
     VFVDIKIDAS EHVYPMQIRD GGMNNMLLRK NGQK