ID   ILVH_BUCBP              Reviewed;         159 AA.
AC   Q89AP8;
DT   14-NOV-2003, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-2003, sequence version 1.
DT   03-AUG-2022, entry version 105.
DE   RecName: Full=Acetolactate synthase small subunit;
DE            EC=2.2.1.6;
DE   AltName: Full=Acetohydroxy-acid synthase small subunit;
DE            Short=AHAS;
DE            Short=ALS;
GN   Name=ilvH; OrderedLocusNames=bbp_207;
OS   Buchnera aphidicola subsp. Baizongia pistaciae (strain Bp).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Erwiniaceae; Buchnera.
OX   NCBI_TaxID=224915;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Bp;
RX   PubMed=12522265; DOI=10.1073/pnas.0235981100;
RA   van Ham R.C.H.J., Kamerbeek J., Palacios C., Rausell C., Abascal F.,
RA   Bastolla U., Fernandez J.M., Jimenez L., Postigo M., Silva F.J.,
RA   Tamames J., Viguera E., Latorre A., Valencia A., Moran F., Moya A.;
RT   "Reductive genome evolution in Buchnera aphidicola.";
RL   Proc. Natl. Acad. Sci. U.S.A. 100:581-586(2003).
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   -!- 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   -!- SIMILARITY: Belongs to the acetolactate synthase small subunit family.
CC       {ECO:0000305}.
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DR   EMBL; AE016826; AAO26939.1; -; Genomic_DNA.
DR   RefSeq; WP_011091340.1; NC_004545.1.
DR   AlphaFoldDB; Q89AP8; -.
DR   SMR; Q89AP8; -.
DR   STRING; 224915.bbp_207; -.
DR   PRIDE; Q89AP8; -.
DR   EnsemblBacteria; AAO26939; AAO26939; bbp_207.
DR   GeneID; 56470749; -.
DR   KEGG; bab:bbp_207; -.
DR   eggNOG; COG0440; Bacteria.
DR   HOGENOM; CLU_055003_1_3_6; -.
DR   OMA; RMFNIES; -.
DR   OrthoDB; 1500398at2; -.
DR   UniPathway; UPA00047; UER00055.
DR   UniPathway; UPA00049; UER00059.
DR   Proteomes; UP000000601; Chromosome.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProt.
DR   GO; GO:0003984; F:acetolactate synthase activity; IEA:UniProtKB-EC.
DR   GO; GO:1990610; F:acetolactate synthase regulator activity; 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; cd04878; ACT_AHAS; 1.
DR   Gene3D; 3.30.70.1150; -; 1.
DR   InterPro; IPR004789; Acetalactate_synth_ssu.
DR   InterPro; IPR027271; Acetolactate_synth/TF_NikR_C.
DR   InterPro; IPR019455; Acetolactate_synth_ssu_C.
DR   InterPro; IPR045865; ACT-like_dom_sf.
DR   InterPro; IPR002912; ACT_dom.
DR   InterPro; IPR039557; AHAS_ACT.
DR   PANTHER; PTHR30239; PTHR30239; 1.
DR   Pfam; PF10369; ALS_ss_C; 1.
DR   SUPFAM; SSF55021; SSF55021; 2.
DR   TIGRFAMs; TIGR00119; acolac_sm; 1.
DR   PROSITE; PS51671; ACT; 1.
PE   3: Inferred from homology;
KW   Amino-acid biosynthesis; Branched-chain amino acid biosynthesis;
KW   Reference proteome; Transferase.
FT   CHAIN           1..159
FT                   /note="Acetolactate synthase small subunit"
FT                   /id="PRO_0000151409"
FT   DOMAIN          5..79
FT                   /note="ACT"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01007"
SQ   SEQUENCE   159 AA;  18174 MW;  6D4B6883C3C4C881 CRC64;
     MKHRILSILL ENESGALSRV VGLFSQRGYN IESITVAPTE DLSISKITIQ TFGDKKVIEQ
     IGKQLHKLID VLKVTEIEDE EHFKREIMLI KINNTYDQYR KVQDITNAFR GYIISATSNI
     SIIQLSGTNK NLDTYIEIMK KLTNIIEISR SGIISIYKN