ID   ILVB_ARTPT              Reviewed;         579 AA.
AC   P27868;
DT   01-AUG-1992, integrated into UniProtKB/Swiss-Prot.
DT   01-AUG-1992, sequence version 1.
DT   03-AUG-2022, entry version 99.
DE   RecName: Full=Acetolactate synthase;
DE            EC=2.2.1.6;
DE   AltName: Full=ALS;
DE   AltName: Full=Acetohydroxy-acid synthase;
DE   Flags: Fragment;
GN   Name=ilvY;
OS   Arthrospira platensis (Spirulina platensis).
OC   Bacteria; Cyanobacteria; Oscillatoriophycideae; Oscillatoriales;
OC   Microcoleaceae; Arthrospira.
OX   NCBI_TaxID=118562;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=1512571; DOI=10.1099/00221287-138-7-1399;
RA   Milano A., de Rossi E., Zanaria E., Barbierato L., Ciferri O., Riccardi G.;
RT   "Molecular characterization of the genes encoding acetohydroxy acid
RT   synthase in the cyanobacterium Spirulina platensis.";
RL   J. Gen. Microbiol. 138:1399-1408(1992).
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   -!- SIMILARITY: Belongs to the TPP enzyme family. {ECO:0000305}.
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DR   EMBL; M75907; AAA26595.1; -; Genomic_DNA.
DR   PIR; B44857; B44857.
DR   AlphaFoldDB; P27868; -.
DR   SMR; P27868; -.
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; 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.
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..>579
FT                   /note="Acetolactate synthase"
FT                   /id="PRO_0000090813"
FT   REGION          408..487
FT                   /note="Thiamine pyrophosphate binding"
FT   BINDING         61
FT                   /ligand="thiamine diphosphate"
FT                   /ligand_id="ChEBI:CHEBI:58937"
FT                   /evidence="ECO:0000250"
FT   BINDING         163
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
FT   BINDING         274..295
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
FT   BINDING         317..336
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
FT   BINDING         458
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000250"
FT   BINDING         485
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000250"
FT   NON_TER         579
SQ   SEQUENCE   579 AA;  63440 MW;  BC94FEA728A7889A CRC64;
     MQDQKQAVKR VTGAFALIDS LRRHGVQHIF GYPGGSNLPI YDEIYRAEQA GEIKHYLVRH
     EQGAAHAADG YARSTGKVGV CLATSGPGAT NLVTGLATAY LDSVPVLAIT GQVPRSALGT
     DAFQEIDIFG ITLPIVKHSY LVREPSELPR IVVEAFHLAM SGRPGPVLID IPKDVGNAQI
     DYIPVEPGSV RRVGYRPTER GNPRQINQAL QLISEATKPL LYVGGGAIMA GAHAEIAELS
     ERFQIPVTST LMGKGRFDEN HPLSLGIVGM LGMHGTAYAN FAVMELDFVI AVGVRFDDRV
     AGTGDQFAHS AKVIHIDIDP AEVGKNRSTD VPIVGDVRQV LGDMLQRTYH WERKLSRNKP
     RNGTDLNQLR EPIPLTVPHP EDGISPQDGD WELSHQCPDA FYTTDVGQHQ MWAGQFVQNG
     PRRWMTSGGL GTMGYGLPAA VGVKVAHPHD TVTCISGDGS FQMNMQELGT IAQYGIGVKV
     IILNNGWLGM VRQWQHMFYN DRYEATNLED GTPEFARLAD VYGLEAMNVR QRKIYQRRLP
     KALSHKGPMI LDVRVTRDED CYPMVAPGHD NSDMMGLSS