ID   ILVH_SYNY3              Reviewed;         172 AA.
AC   Q55141;
DT   30-MAY-2000, integrated into UniProtKB/Swiss-Prot.
DT   30-MAY-2000, sequence version 2.
DT   25-MAY-2022, entry version 129.
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; Synonyms=ilvN; OrderedLocusNames=sll0065;
OS   Synechocystis sp. (strain PCC 6803 / Kazusa).
OC   Bacteria; Cyanobacteria; Synechococcales; Merismopediaceae; Synechocystis;
OC   unclassified Synechocystis.
OX   NCBI_TaxID=1111708;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 27184 / PCC 6803 / N-1;
RX   PubMed=8590279; DOI=10.1093/dnares/2.4.153;
RA   Kaneko T., Tanaka A., Sato S., Kotani H., Sazuka T., Miyajima N.,
RA   Sugiura M., Tabata S.;
RT   "Sequence analysis of the genome of the unicellular cyanobacterium
RT   Synechocystis sp. strain PCC6803. I. Sequence features in the 1 Mb region
RT   from map positions 64% to 92% of the genome.";
RL   DNA Res. 2:153-166(1995).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=PCC 6803 / Kazusa;
RX   PubMed=8905231; DOI=10.1093/dnares/3.3.109;
RA   Kaneko T., Sato S., Kotani H., Tanaka A., Asamizu E., Nakamura Y.,
RA   Miyajima N., Hirosawa M., Sugiura M., Sasamoto S., Kimura T., Hosouchi T.,
RA   Matsuno A., Muraki A., Nakazaki N., Naruo K., Okumura S., Shimpo S.,
RA   Takeuchi C., Wada T., Watanabe A., Yamada M., Yasuda M., Tabata S.;
RT   "Sequence analysis of the genome of the unicellular cyanobacterium
RT   Synechocystis sp. strain PCC6803. II. Sequence determination of the entire
RT   genome and assignment of potential protein-coding regions.";
RL   DNA Res. 3:109-136(1996).
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}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=BAA10276.1; Type=Erroneous initiation; Evidence={ECO:0000305};
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DR   EMBL; BA000022; BAA10276.1; ALT_INIT; Genomic_DNA.
DR   PIR; S74358; S74358.
DR   AlphaFoldDB; Q55141; -.
DR   SMR; Q55141; -.
DR   IntAct; Q55141; 2.
DR   STRING; 1148.1001135; -.
DR   PaxDb; Q55141; -.
DR   EnsemblBacteria; BAA10276; BAA10276; BAA10276.
DR   KEGG; syn:sll0065; -.
DR   eggNOG; COG0440; Bacteria.
DR   InParanoid; Q55141; -.
DR   OMA; EPYGIKE; -.
DR   PhylomeDB; Q55141; -.
DR   UniPathway; UPA00047; UER00055.
DR   UniPathway; UPA00049; UER00059.
DR   Proteomes; UP000001425; Chromosome.
DR   GO; GO:0005829; C:cytosol; IBA:GO_Central.
DR   GO; GO:0003984; F:acetolactate synthase activity; IBA:GO_Central.
DR   GO; GO:1990610; F:acetolactate synthase regulator activity; IEA:InterPro.
DR   GO; GO:0009097; P:isoleucine biosynthetic process; IBA:GO_Central.
DR   GO; GO:0009099; P:valine biosynthetic process; IBA:GO_Central.
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..172
FT                   /note="Acetolactate synthase small subunit"
FT                   /id="PRO_0000151418"
FT   DOMAIN          4..78
FT                   /note="ACT"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01007"
SQ   SEQUENCE   172 AA;  18871 MW;  CF266998F9BCA806 CRC64;
     MKHTLSVLVE DEAGVLTRIA GLFARRGFNI ESLAVGSAEQ GDVSRITMVV PGDENTIEQL
     TKQLYKLVNV IKVQDITETP CVERELMLVK VSANAPNRAE VIELAQVFRA RIVDISEDTV
     TIEVVGDPGK MVAILQMLAK FGIKEVARTG KIALVRESGV NTEYLKSLES KF