ID   FABH_TRIV2              Reviewed;         330 AA.
AC   Q3M9J4;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   25-OCT-2005, sequence version 1.
DT   25-MAY-2022, entry version 92.
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=Ava_2729;
OS   Trichormus variabilis (strain ATCC 29413 / PCC 7937) (Anabaena variabilis).
OC   Bacteria; Cyanobacteria; Nostocales; Nostocaceae; Trichormus.
OX   NCBI_TaxID=240292;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 29413 / PCC 7937;
RX   PubMed=25197444; DOI=10.4056/sigs.3899418;
RA   Thiel T., Pratte B.S., Zhong J., Goodwin L., Copeland A., Lucas S., Han C.,
RA   Pitluck S., Land M.L., Kyrpides N.C., Woyke T.;
RT   "Complete genome sequence of Anabaena variabilis ATCC 29413.";
RL   Stand. Genomic Sci. 9:562-573(2014).
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; CP000117; ABA22342.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q3M9J4; -.
DR   SMR; Q3M9J4; -.
DR   STRING; 240292.Ava_2729; -.
DR   EnsemblBacteria; ABA22342; ABA22342; Ava_2729.
DR   KEGG; ava:Ava_2729; -.
DR   eggNOG; COG0332; Bacteria.
DR   HOGENOM; CLU_039592_0_1_3; -.
DR   OMA; WGSEGDK; -.
DR   UniPathway; UPA00094; -.
DR   Proteomes; UP000002533; 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; Transferase.
FT   CHAIN           1..330
FT                   /note="3-oxoacyl-[acyl-carrier-protein] synthase 3"
FT                   /id="PRO_1000056323"
FT   REGION          256..260
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        255
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01815"
FT   ACT_SITE        285
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01815"
SQ   SEQUENCE   330 AA;  35385 MW;  EB62C103768C2FE2 CRC64;
     MQNLGIAITG SGSAAPETSL HNEELSQLVE TSDEWISTRT GIRQRRLALP TESLSSLAAA
     ASRQAIASAG ITASDIDLIL LATSTPDDLF GTATKIQAEL GATKAVAFDL TAACSGFVFG
     LVTAAQFIRT GVYQNVLLIG ADILSRWVDW QDRRTCVLFG DGAGAIVLQS NQSDRLLGFA
     LKSDGTQNHY LNLAYQGTAQ EILPNIKITQ GTYQPVTMNG KEVYRFAAQK VPEIIDKALF
     EANITVDQID WLLLHQANQR ILDTVAQRLN IPAHKVISNL ANYGNTSAAS IPLALDEAVR
     EGKIKPNDII ATSGFGAGLT WGAAIFQWGR