ID   ILVB_GUITH              Reviewed;         575 AA.
AC   O78518;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1998, sequence version 1.
DT   03-AUG-2022, entry version 115.
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=ilvB;
OS   Guillardia theta (Cryptophyte) (Cryptomonas phi).
OG   Plastid; Chloroplast.
OC   Eukaryota; Cryptophyceae; Pyrenomonadales; Geminigeraceae; Guillardia.
OX   NCBI_TaxID=55529;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RX   PubMed=9929392; DOI=10.1007/pl00006462;
RA   Douglas S.E., Penny S.L.;
RT   "The plastid genome of the cryptophyte alga, Guillardia theta: complete
RT   sequence and conserved synteny groups confirm its common ancestry with red
RT   algae.";
RL   J. Mol. Evol. 48:236-244(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   -!- SUBCELLULAR LOCATION: Plastid, chloroplast.
CC   -!- SIMILARITY: Belongs to the TPP enzyme family. {ECO:0000305}.
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DR   EMBL; AF041468; AAC35740.1; -; Genomic_DNA.
DR   RefSeq; NP_050806.1; NC_000926.1.
DR   AlphaFoldDB; O78518; -.
DR   SMR; O78518; -.
DR   GeneID; 857117; -.
DR   HOGENOM; CLU_013748_1_2_1; -.
DR   OMA; CFGTSGP; -.
DR   UniPathway; UPA00047; UER00055.
DR   UniPathway; UPA00049; UER00059.
DR   GO; GO:0009507; C:chloroplast; IEA:UniProtKB-SubCell.
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;
KW   Chloroplast; FAD; Flavoprotein; Magnesium; Metal-binding; Plastid;
KW   Thiamine pyrophosphate; Transferase.
FT   CHAIN           1..575
FT                   /note="Acetolactate synthase large subunit"
FT                   /id="PRO_0000090810"
FT   REGION          404..483
FT                   /note="Thiamine pyrophosphate binding"
FT   BINDING         60
FT                   /ligand="thiamine diphosphate"
FT                   /ligand_id="ChEBI:CHEBI:58937"
FT                   /evidence="ECO:0000250"
FT   BINDING         162
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
FT   BINDING         270..291
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
FT   BINDING         313..332
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
FT   BINDING         454
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000250"
FT   BINDING         481
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   575 AA;  63360 MW;  F9447F9A178D3EC4 CRC64;
     MPNILKNRDT TGAFALIDSL VRHGVKHIFG YPGGAILPIY DELYAWEKEG FIEHILVRHE
     QGAAHASDGY ARSTGNVGVC FATSGPGATN LVTGIATAHM DSVPMVIITG QVGRSFIGTD
     AFQEVDIFGI TLPIVKHSYV VRETKEMGKI VAESFFIAKY GRPGPVLIDI PKDVGLEKFD
     YQIVNPNNIN LAGCPVLKNY DQNRISQAAN LIKQSSQPLL YIGGGAVTSN SHNEINELIN
     LVKIPVATTL MGKGIIDESH PLSLGMLGMH GTVYANYAVS ECDLLIALGA RFDDRVTGKL
     DEFACHAQVI HVDIDPAEIG KNRTPQIGIV GEIKDFVRDL IECLKNDINF DSEQSQAWRS
     RIIRWRKEYP LLVPKNINNL SPQEVIHEIS TEATNAYFTT DVGQHQMWAA QFIKTSQKRW
     ITSAGLGTMG YGLPAAIGVQ IAHPNEQVIC ISGDASFQMN IQELGTVSQY GLPIKIFIIN
     NKWQGMVRQW QQAFYGERYS HSNMEKGAPN FTKVAEAFGL RSLKIKSRND LKLRIKEALD
     YDGPILVDIQ VIADENCYPM VAPGKSNAQM MGINS