ID   ILVH_BUCAP              Reviewed;         158 AA.
AC   O85294;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1998, sequence version 1.
DT   03-AUG-2022, entry version 122.
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=BUsg_219;
OS   Buchnera aphidicola subsp. Schizaphis graminum (strain Sg).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Erwiniaceae; Buchnera.
OX   NCBI_TaxID=198804;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=9688822; DOI=10.1007/s002849900365;
RA   Thao M.L., Baumann P.;
RT   "Sequence analysis of a DNA fragment from Buchnera aphidicola (Aphid
RT   endosymbiont) containing the genes dapD-htrA-ilvI-ilvH-ftsL-ftsI-murE.";
RL   Curr. Microbiol. 37:214-216(1998).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Sg;
RX   PubMed=12089438; DOI=10.1126/science.1071278;
RA   Tamas I., Klasson L., Canbaeck B., Naeslund A.K., Eriksson A.-S.,
RA   Wernegreen J.J., Sandstroem J.P., Moran N.A., Andersson S.G.E.;
RT   "50 million years of genomic stasis in endosymbiotic bacteria.";
RL   Science 296:2376-2379(2002).
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; AF060492; AAC32334.1; -; Genomic_DNA.
DR   EMBL; AE013218; AAM67779.1; -; Genomic_DNA.
DR   RefSeq; WP_011053746.1; NC_004061.1.
DR   AlphaFoldDB; O85294; -.
DR   SMR; O85294; -.
DR   STRING; 198804.BUsg_219; -.
DR   EnsemblBacteria; AAM67779; AAM67779; BUsg_219.
DR   KEGG; bas:BUsg_219; -.
DR   eggNOG; COG0440; Bacteria.
DR   HOGENOM; CLU_055003_1_3_6; -.
DR   OMA; EPYGIKE; -.
DR   OrthoDB; 1500398at2; -.
DR   UniPathway; UPA00047; UER00055.
DR   UniPathway; UPA00049; UER00059.
DR   Proteomes; UP000000416; 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   Transferase.
FT   CHAIN           1..158
FT                   /note="Acetolactate synthase small subunit"
FT                   /id="PRO_0000151408"
FT   DOMAIN          4..78
FT                   /note="ACT"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01007"
SQ   SEQUENCE   158 AA;  17776 MW;  C4D7AE2552040416 CRC64;
     MRRILSVLLE NESGALSRVI GLFSQRGYNI ETITVAPTED PSLSKMTIQT IGNEKSIEQI
     EKQLHKLIDV LRVIKVGQNS HIEREIMLLK VQTNNCKKDD VKHITEVFRG QIVDITSTTY
     VLQITGTAKK LDSFLKIIRN TTEIIEMTRS GIVGIARG