ID   FABH_SYNR3              Reviewed;         333 AA.
AC   A5GQJ2;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   12-JUN-2007, sequence version 1.
DT   25-MAY-2022, entry version 73.
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};
GN   OrderedLocusNames=SynRCC307_0248;
OS   Synechococcus sp. (strain RCC307).
OC   Bacteria; Cyanobacteria; Synechococcales; Synechococcaceae; Synechococcus;
OC   unclassified Synechococcus.
OX   NCBI_TaxID=316278;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=RCC307;
RG   Genoscope;
RL   Submitted (MAY-2006) to the EMBL/GenBank/DDBJ databases.
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; CT978603; CAK27151.1; -; Genomic_DNA.
DR   RefSeq; WP_011934666.1; NC_009482.1.
DR   AlphaFoldDB; A5GQJ2; -.
DR   SMR; A5GQJ2; -.
DR   STRING; 316278.SynRCC307_0248; -.
DR   EnsemblBacteria; CAK27151; CAK27151; SynRCC307_0248.
DR   KEGG; syr:SynRCC307_0248; -.
DR   eggNOG; COG0332; Bacteria.
DR   HOGENOM; CLU_039592_0_1_3; -.
DR   OMA; WGSEGDK; -.
DR   OrthoDB; 872193at2; -.
DR   UniPathway; UPA00094; -.
DR   Proteomes; UP000001115; 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..333
FT                   /note="3-oxoacyl-[acyl-carrier-protein] synthase 3"
FT                   /id="PRO_1000056435"
FT   REGION          256..260
FT                   /note="ACP-binding"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01815"
FT   ACT_SITE        112
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   333 AA;  34887 MW;  1595E4969C71DF2C CRC64;
     MKGIRLCGSG AAVPRLRISN DDLSGRVETS DEWIRTRTGI AARRVADESE SLTSLAAAAG
     KQALERAGWD ASSVDLILLA TSSPDDLFGS APKVQALIGA GSAVAFDLTA ACSGFLFSLV
     TAAQYLRTGA MTRALVIGAD QLSRWVDWDD RRSCVLFGDG AGAVAIEACP AENDGLLGFR
     LNSDGARGDC LTLAQTSERA ELLPGMSHQR GGYAPIGMNG QEVYKFAVRE VPAILKQLLA
     DTNTEPASID WLLLHQANQR ILDAAAERLG IAADKVLSNL ANYGNTSAGT IPLMLHEAVS
     DGRIQSGQLI ASSGFGAGLS WGAALLRWDG PTS