ID   ILVB_PORUM              Reviewed;         590 AA.
AC   P69684; P31594;
DT   29-MAR-2005, integrated into UniProtKB/Swiss-Prot.
DT   29-MAR-2005, sequence version 1.
DT   03-AUG-2022, entry version 63.
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   Porphyra umbilicalis (Purple laver) (Red alga).
OG   Plastid; Chloroplast.
OC   Eukaryota; Rhodophyta; Bangiophyceae; Bangiales; Bangiaceae; Porphyra.
OX   NCBI_TaxID=2786;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=Avonport;
RX   PubMed=8381336; DOI=10.1007/bf00336751;
RA   Reith M., Munholland J.M.;
RT   "Two amino-acid biosynthetic genes are encoded on the plastid genome of the
RT   red alga Porphyra umbilicalis.";
RL   Curr. Genet. 23:59-65(1993).
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; M94625; AAA03052.1; -; Unassigned_DNA.
DR   PIR; S28920; S28920.
DR   AlphaFoldDB; P69684; -.
DR   SMR; P69684; -.
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..590
FT                   /note="Acetolactate synthase large subunit"
FT                   /id="PRO_0000090812"
FT   REGION          405..484
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         271..292
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
FT   BINDING         314..333
FT                   /ligand="FAD"
FT                   /ligand_id="ChEBI:CHEBI:57692"
FT                   /evidence="ECO:0000250"
FT   BINDING         455
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000250"
FT   BINDING         482
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   590 AA;  64930 MW;  1C35F7DF0F2E97AD CRC64;
     MLSKQIIGSE KTGRFALLDS IVRHGVIHIF GYPGGAILPI YDELYAWEEL SLIKNILVRH
     EQGASHAADA YSRSTGKVGV CFATSGPGAT NLVSGIATAH IDSVPILAIT GQVGRPFIGT
     DAFQEVDIFG ITLPIVKHSY VVRDPRDMSR IVAEAFYICK HGRPGPVLID VPKDVGLEKF
     NYFSVEPGQV KIPGCRPLSN LKSRQILMAA KMIQQSSQPL LYIGGGAIIS DAHSIIKELV
     DLYKIPVTTT LMGKGIFNED SEFCLGMLGM HGTAYANFAV SECDLLIALG ARFDDRVTGK
     LDEFACNAQV IHVDIDPAEV GKNRIPQVAI VGDVTEVVTS LLNLLKNNFK PYPEQIISWQ
     ERIHRWRQQY PLLVPKKSTS ISPQEILVTT NQLAQDAYFT TDVGQHQMWS AQFLKVKSKH
     WISSAGLGTM GYGLPAAIGA QVAHPNELVI CVSGDSSFQM NMQELGTIAQ YKLPIKIVII
     NNRWQGMVRQ WQQAFYGERY SHSRMTEGAP NFQKLAEAFG IKAFTVNNRQ NMESSLKDAM
     KYPGPVLLDC QVTENENCYP MVAPGKSNAQ MIGIAKPQRG TASNYVSRNI