ID   FABH_PROMT              Reviewed;         338 AA.
AC   Q46HN8;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   13-SEP-2005, sequence version 1.
DT   25-MAY-2022, entry version 90.
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=PMN2A_1502;
OS   Prochlorococcus marinus (strain NATL2A).
OC   Bacteria; Cyanobacteria; Synechococcales; Prochlorococcaceae;
OC   Prochlorococcus.
OX   NCBI_TaxID=59920;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=NATL2A;
RX   PubMed=18159947; DOI=10.1371/journal.pgen.0030231;
RA   Kettler G.C., Martiny A.C., Huang K., Zucker J., Coleman M.L., Rodrigue S.,
RA   Chen F., Lapidus A., Ferriera S., Johnson J., Steglich C., Church G.M.,
RA   Richardson P., Chisholm S.W.;
RT   "Patterns and implications of gene gain and loss in the evolution of
RT   Prochlorococcus.";
RL   PLoS Genet. 3:2515-2528(2007).
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; CP000095; AAZ58990.1; -; Genomic_DNA.
DR   RefSeq; WP_011294135.1; NC_007335.2.
DR   AlphaFoldDB; Q46HN8; -.
DR   SMR; Q46HN8; -.
DR   STRING; 59920.PMN2A_1502; -.
DR   EnsemblBacteria; AAZ58990; AAZ58990; PMN2A_1502.
DR   KEGG; pmn:PMN2A_1502; -.
DR   HOGENOM; CLU_039592_0_1_3; -.
DR   OMA; WGSEGDK; -.
DR   OrthoDB; 872193at2; -.
DR   PhylomeDB; Q46HN8; -.
DR   UniPathway; UPA00094; -.
DR   Proteomes; UP000002535; 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..338
FT                   /note="3-oxoacyl-[acyl-carrier-protein] synthase 3"
FT                   /id="PRO_1000056391"
FT   REGION          262..266
FT                   /note="ACP-binding"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01815"
FT   ACT_SITE        119
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01815"
FT   ACT_SITE        261
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01815"
FT   ACT_SITE        291
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01815"
SQ   SEQUENCE   338 AA;  36349 MW;  7EFB2807877AA4F8 CRC64;
     MISNSQLDLG ISFVGSGSAT PQKIIKNDQL GQRVDTNDEW IQTRTGIGQR RVIGENESLI
     DLATDAAVNA VKMADWDVQT IDLIILATST PEDLFGSAPK IQSNLGASNA VAFDLTAACS
     GFLFALVTAS QYLASGSMKR ALVIGADQLS KWVDWDDRKT CVLFGDGAGA VALESSGDES
     GLIGYDLKSD GSKGGCLNLS QSNVFLDLVQ GANHQKGEYL PIKMEGKEVY KFAVKEVPII
     LGEILEKCQI KSESIDWLLL HQANQRILDA VASRFSIPSE KVLSNLKYYG NTSAATIPLM
     LDEAVRDKRI KSGDLIACSG FGAGLSWGAA LFYWHGPY