ID   FABH_THIDA              Reviewed;         319 AA.
AC   Q3SIM4;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   11-OCT-2005, sequence version 1.
DT   25-MAY-2022, entry version 101.
DE   RecName: Full=3-oxoacyl-[acyl-carrier-protein] synthase 3 {ECO:0000255|HAMAP-Rule:MF_01815};
DE            EC=2.3.1.180 {ECO:0000255|HAMAP-Rule:MF_01815};
DE   AltName: Full=3-oxoacyl-[acyl-carrier-protein] synthase III {ECO:0000255|HAMAP-Rule:MF_01815};
DE   AltName: Full=Beta-ketoacyl-ACP synthase III {ECO:0000255|HAMAP-Rule:MF_01815};
DE            Short=KAS III {ECO:0000255|HAMAP-Rule:MF_01815};
GN   Name=fabH {ECO:0000255|HAMAP-Rule:MF_01815}; OrderedLocusNames=Tbd_1551;
OS   Thiobacillus denitrificans (strain ATCC 25259).
OC   Bacteria; Proteobacteria; Betaproteobacteria; Nitrosomonadales;
OC   Thiobacillaceae; Thiobacillus.
OX   NCBI_TaxID=292415;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 25259;
RX   PubMed=16452431; DOI=10.1128/jb.188.4.1473-1488.2006;
RA   Beller H.R., Chain P.S., Letain T.E., Chakicherla A., Larimer F.W.,
RA   Richardson P.M., Coleman M.A., Wood A.P., Kelly D.P.;
RT   "The genome sequence of the obligately chemolithoautotrophic, facultatively
RT   anaerobic bacterium Thiobacillus denitrificans.";
RL   J. Bacteriol. 188:1473-1488(2006).
CC   -!- FUNCTION: Catalyzes the condensation reaction of fatty acid synthesis
CC       by the addition to an acyl acceptor of two carbons from malonyl-ACP.
CC       Catalyzes the first condensation reaction which initiates fatty acid
CC       synthesis and may therefore play a role in governing the total rate of
CC       fatty acid production. Possesses both acetoacetyl-ACP synthase and
CC       acetyl transacylase activities. Its substrate specificity determines
CC       the biosynthesis of branched-chain and/or straight-chain of fatty
CC       acids. {ECO:0000255|HAMAP-Rule:MF_01815}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=acetyl-CoA + H(+) + malonyl-[ACP] = 3-oxobutanoyl-[ACP] + CO2
CC         + CoA; Xref=Rhea:RHEA:12080, Rhea:RHEA-COMP:9623, Rhea:RHEA-
CC         COMP:9625, ChEBI:CHEBI:15378, ChEBI:CHEBI:16526, ChEBI:CHEBI:57287,
CC         ChEBI:CHEBI:57288, ChEBI:CHEBI:78449, ChEBI:CHEBI:78450;
CC         EC=2.3.1.180; Evidence={ECO:0000255|HAMAP-Rule:MF_01815};
CC   -!- PATHWAY: Lipid metabolism; fatty acid biosynthesis. {ECO:0000255|HAMAP-
CC       Rule:MF_01815}.
CC   -!- SUBUNIT: Homodimer. {ECO:0000255|HAMAP-Rule:MF_01815}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000255|HAMAP-Rule:MF_01815}.
CC   -!- DOMAIN: The last Arg residue of the ACP-binding site is essential for
CC       the weak association between ACP/AcpP and FabH. {ECO:0000255|HAMAP-
CC       Rule:MF_01815}.
CC   -!- SIMILARITY: Belongs to the thiolase-like superfamily. FabH family.
CC       {ECO:0000255|HAMAP-Rule:MF_01815}.
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DR   EMBL; CP000116; AAZ97504.1; -; Genomic_DNA.
DR   RefSeq; WP_011312063.1; NC_007404.1.
DR   AlphaFoldDB; Q3SIM4; -.
DR   SMR; Q3SIM4; -.
DR   STRING; 292415.Tbd_1551; -.
DR   EnsemblBacteria; AAZ97504; AAZ97504; Tbd_1551.
DR   KEGG; tbd:Tbd_1551; -.
DR   eggNOG; COG0332; Bacteria.
DR   HOGENOM; CLU_039592_4_1_4; -.
DR   OMA; WGSEGDK; -.
DR   OrthoDB; 872193at2; -.
DR   UniPathway; UPA00094; -.
DR   Proteomes; UP000008291; Chromosome.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0004315; F:3-oxoacyl-[acyl-carrier-protein] synthase activity; IEA:InterPro.
DR   GO; GO:0033818; F:beta-ketoacyl-acyl-carrier-protein synthase III activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0006633; P:fatty acid biosynthetic process; IEA:UniProtKB-UniRule.
DR   Gene3D; 3.40.47.10; -; 1.
DR   HAMAP; MF_01815; FabH; 1.
DR   InterPro; IPR013751; ACP_syn_III.
DR   InterPro; IPR013747; ACP_syn_III_C.
DR   InterPro; IPR004655; FabH_synth.
DR   InterPro; IPR016039; Thiolase-like.
DR   Pfam; PF08545; ACP_syn_III; 1.
DR   Pfam; PF08541; ACP_syn_III_C; 1.
DR   SUPFAM; SSF53901; SSF53901; 1.
DR   TIGRFAMs; TIGR00747; fabH; 1.
PE   3: Inferred from homology;
KW   Acyltransferase; Cytoplasm; Fatty acid biosynthesis; Fatty acid metabolism;
KW   Lipid biosynthesis; Lipid metabolism; Multifunctional enzyme;
KW   Reference proteome; Transferase.
FT   CHAIN           1..319
FT                   /note="3-oxoacyl-[acyl-carrier-protein] synthase 3"
FT                   /id="PRO_1000056437"
FT   REGION          247..251
FT                   /note="ACP-binding"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01815"
FT   ACT_SITE        114
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01815"
FT   ACT_SITE        246
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01815"
FT   ACT_SITE        276
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01815"
SQ   SEQUENCE   319 AA;  33691 MW;  746E75C82CE0E51D CRC64;
     MTYSRILGTG GYLPARILTN ADLEKLVDTN DQWIVDRTGI RERHIAADGE FTSDLATAAA
     RAALEAANLA ADDIDLLLVA TTTPDLVFPS TACIVQSKLG MTNGKPAFDL QAVCSGFVYA
     LSVADQFIKG GAAKHVLVVG AETLSRITDW NDRSNCILWG DGAGAVVVGA SSEPGIIATH
     IHADGRHKEL LRTTTGPSSG SKTPALMRME GNAVFKMAVN TLDRIVDETL EANGLAKTDI
     DWLVPHQANI RIISATAKKL GMSMDNVVTT VAGHGNTSAA SVPLAFDAAV RDGRIKRGQI
     VLMEAFGGGF TWGSALLRY