HAMAP rule MF_01815
General rule information
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| PURL | https://purl.expasy.org/hamap/rule/MF_01815 |
| Accession | MF_01815 |
| Dates | 28-FEB-2005 (Created)
25-AUG-2025 (Last updated, Version 40) |
| Name | FabH |
| Scope(s) |
Bacteria Plastid |
| Template(s) | P0A6R0; O34746; O07600; P0A3C5; Q54206; Q4URQ0; C0LNR0; P9WNG3; P68795; Q9F6D4; [ Recover all ] |
| Triggered by |
HAMAP; MF_01815 (Get profile general information and statistics) |
Propagated annotation
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Identifier, protein and gene names
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| case not <OC:Mycobacterium> | |
| Identifier | FABH |
| Protein name | RecName: Full=Beta-ketoacyl-[acyl-carrier-protein] synthase III; Short=Beta-ketoacyl-ACP synthase III; Short=KAS III; EC=2.3.1.180; AltName: Full=3-oxoacyl-[acyl-carrier-protein] synthase 3; AltName: Full=3-oxoacyl-[acyl-carrier-protein] synthase III; |
| Gene name | Name=fabH; |
| else case <OC:Mycobacterium> | |
| Identifier | FABH |
| Protein name | RecName: Full=Mycobacterial beta-ketoacyl-[acyl-carrier-protein] synthase III; Short=Beta-ketoacyl-ACP synthase III; Short=KAS III; EC=2.3.1.301; AltName: Full=3-oxoacyl-[acyl-carrier-protein] synthase 3; AltName: Full=3-oxoacyl-[acyl-carrier-protein] synthase III; |
| Gene name | Name=fabH; |
| end case | |
Comments
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| FUNCTION | Catalyzes the condensation reaction of fatty acid synthesis by the addition to an acyl acceptor of two carbons from malonyl-ACP. Catalyzes the first condensation reaction which initiates fatty acid synthesis and may therefore play a role in governing the total rate of fatty acid production. Possesses both acetoacetyl-ACP synthase and acetyl transacylase activities. Its substrate specificity determines the biosynthesis of branched-chain and/or straight-chain of fatty acids. |
| case not <OC:Mycobacterium> | |
| CATALYTIC ACTIVITY | Reaction=malonyl-[ACP] + acetyl-CoA + H(+) = 3-oxobutanoyl-[ACP] + CO2 + CoA; Xref=Rhea:RHEA:12080, Rhea:RHEA-COMP:9623, Rhea:RHEA- COMP:9625, ChEBI:CHEBI:15378, ChEBI:CHEBI:16526, ChEBI:CHEBI:57287, ChEBI:CHEBI:57288, ChEBI:CHEBI:78449, ChEBI:CHEBI:78450; EC=2.3.1.180; |
| else case <OC:Mycobacterium> | |
| CATALYTIC ACTIVITY | Reaction=malonyl-[ACP] + dodecanoyl-CoA + H(+) = 3-oxotetradecanoyl- [ACP] + CO2 + CoA; Xref=Rhea:RHEA:43640, Rhea:RHEA-COMP:9623, Rhea:RHEA-COMP:9645, ChEBI:CHEBI:15378, ChEBI:CHEBI:16526, ChEBI:CHEBI:57287, ChEBI:CHEBI:57375, ChEBI:CHEBI:78449, ChEBI:CHEBI:78473; EC=2.3.1.301; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:43641; |
| end case | |
| PATHWAY | Lipid metabolism; fatty acid biosynthesis. |
| case <OC:Mycobacterium> | |
| PATHWAY | Lipid metabolism; mycolic acid biosynthesis. |
| end case | |
| SUBUNIT | Homodimer. |
| case <OG:Chloroplast> | |
| SUBCELLULAR LOCATION | Plastid, chloroplast. |
| end case | |
| case not <OG:Chloroplast> | |
| SUBCELLULAR LOCATION | Cytoplasm. |
| end case | |
| DOMAIN | The last Arg residue of the ACP-binding site is essential for the weak association between ACP/AcpP and FabH. |
| SIMILARITY | Belongs to the thiolase-like superfamily. FabH family. |
Keywords
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| Acyltransferase | |
| case not <OG:Chloroplast> | |
| Cytoplasm | |
| end case | |
| Fatty acid biosynthesis | |
| Fatty acid metabolism | |
| Lipid biosynthesis | |
| Lipid metabolism | |
| Multifunctional enzyme | |
| Transferase | |
Gene Ontology
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| GO:0033818; Molecular function:beta-ketoacyl-acyl-carrier-protein synthase III activity | |
| GO:0006633; Biological process:fatty acid biosynthetic process | |
| case <OG:Chloroplast> | |
| GO:0009507; Cellular component:chloroplast | |
| end case | |
| case not <OG:Chloroplast> | |
| GO:0005737; Cellular component:cytoplasm | |
| end case | |
Cross-references
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| NCBIfam | TIGR00747; FabH; 1; |
Features
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| From: FABH_ECOLI (P0A6R0) | ||||||||||||
| Key | From | To | Description | Tag | Condition | FTGroup | ||||||
| ACT_SITE | 112 | 112 | C | |||||||||
| ACT_SITE | 244 | 244 | H | |||||||||
| ACT_SITE | 274 | 274 | N | |||||||||
| REGION | 245 | 249 | /note="ACP-binding" | [QS]-[AP]-N-x-R | ||||||||
Additional information
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| Size range | 309-364 amino acids |
| Related rules |
None |
| Fusion | Nter: None Cter: None |
| Comments | In many organisms this enzyme can accept branched-chain acyl-CoAs (EC 2.3.1.300) in addition to acetyl-CoA. Mycobacterial enzyme acts on medium- and long-chain acyl-CoAs (EC 2.3.1.301) and has no activity with acetyl-CoA or branched-chain acyl-CoAs. |