P0A6R0 · FABH_ECOLI
- ProteinBeta-ketoacyl-[acyl-carrier-protein] synthase III
- GenefabH
- StatusUniProtKB reviewed (Swiss-Prot)
- Organism
- Amino acids317 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
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. Has some substrate specificity for acetyl-CoA. Its substrate specificity determines the biosynthesis of straight-chain of fatty acids instead of branched-chain (PubMed:10629181, PubMed:7592873, PubMed:8631920, PubMed:8910376).
Can also use propionyl-CoA, with lower efficiency (PubMed:10629181, PubMed:8631920).
Can also use propionyl-CoA, with lower efficiency (PubMed:10629181, PubMed:8631920).
Catalytic activity
- acetyl-CoA + H+ + malonyl-[ACP] = 3-oxobutanoyl-[ACP] + CO2 + CoAThis reaction proceeds in the forward direction.
- H+ + malonyl-[ACP] + propanoyl-CoA = 3-oxopentanoyl-[ACP] + CO2 + CoAThis reaction proceeds in the forward direction.
Activity regulation
Negatively regulated by acyl-ACP, possibly by binding to either the free enzyme or the acyl-enzyme intermediate (PubMed:8631920).
Inhibited by the SB418011 antibiotic (PubMed:11375394).
Not inhibited by cerulenin, and weakly inhibited by thiolactomycin (PubMed:11375394).
Inhibited by the SB418011 antibiotic (PubMed:11375394).
Not inhibited by cerulenin, and weakly inhibited by thiolactomycin (PubMed:11375394).
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
40 μM | acetyl-CoA | |||||
5 μM | malonyl-[ACP] |
Pathway
Lipid metabolism; fatty acid biosynthesis.
Features
Showing features for active site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Active site | 112 | |||||
Sequence: C | ||||||
Active site | 244 | |||||
Sequence: H | ||||||
Active site | 274 | |||||
Sequence: N |
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | cytosol | |
Molecular Function | 3-oxoacyl-[acyl-carrier-protein] synthase activity | |
Molecular Function | beta-ketoacyl-acyl-carrier-protein synthase III activity | |
Biological Process | fatty acid biosynthetic process | |
Biological Process | fatty acid metabolic process |
Keywords
- Molecular function
- Biological process
Enzyme and pathway databases
Chemistry
Names & Taxonomy
Protein names
- Recommended nameBeta-ketoacyl-[acyl-carrier-protein] synthase III
- EC number
- Short namesBeta-ketoacyl-ACP synthase III ; KAS III
- Alternative names
Gene names
Organism names
- Organism
- Strains
- Taxonomic lineageBacteria > Pseudomonadota > Gammaproteobacteria > Enterobacterales > Enterobacteriaceae > Escherichia
Accessions
- Primary accessionP0A6R0
- Secondary accessions
Proteomes
Subcellular Location
Phenotypes & Variants
Features
Showing features for mutagenesis.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Mutagenesis | 112 | Loss of activity. | ||||
Sequence: C → S | ||||||
Mutagenesis | 214 | Strongly reduces the binding to malonyl-ACP but not that of the substrate. | ||||
Sequence: K → E or A | ||||||
Mutagenesis | 244 | Loss of activity. | ||||
Sequence: H → A | ||||||
Mutagenesis | 249 | Abolishes the binding to malonyl-ACP but not that of the substrate. | ||||
Sequence: R → E or A | ||||||
Mutagenesis | 253 | Abolishes both binding to malonyl-ACP and binding to substrate. | ||||
Sequence: A → Y | ||||||
Mutagenesis | 256-257 | Strongly reduces both binding to malonyl-ACP and binding to substrate. | ||||
Sequence: KK → AA | ||||||
Mutagenesis | 256-257 | Abolishes the binding to malonyl-ACP but not that of the substrate. | ||||
Sequence: KK → EE | ||||||
Mutagenesis | 274 | Loss of activity. | ||||
Sequence: N → A |
Chemistry
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000110424 | 1-317 | Beta-ketoacyl-[acyl-carrier-protein] synthase III | |||
Sequence: MYTKIIGTGSYLPEQVRTNADLEKMVDTSDEWIVTRTGIRERHIAAPNETVSTMGFEAATRAIEMAGIEKDQIGLIVVATTSATHAFPSAACQIQSMLGIKGCPAFDVAAACAGFTYALSVADQYVKSGAVKYALVVGSDVLARTCDPTDRGTIIIFGDGAGAAVLAASEEPGIISTHLHADGSYGELLTLPNADRVNPENSIHLTMAGNEVFKVAVTELAHIVDETLAANNLDRSQLDWLVPHQANLRIISATAKKLGMSMDNVVVTLDRHGNTSAASVPCALDEAVRDGRIKPGQLVLLEAFGGGFTWGSALVRF |
Proteomic databases
PTM databases
Structure
Family & Domains
Features
Showing features for region.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Region | 245-249 | ACP-binding | ||||
Sequence: QANLR |
Domain
The last Arg residue of the ACP-binding site is essential for the weak association between ACP/AcpP and FabH.
Sequence similarities
Belongs to the thiolase-like superfamily. FabH family.
Phylogenomic databases
Family and domain databases
Sequence
- Sequence statusComplete
- Length317
- Mass (Da)33,515
- Last updated2005-05-10 v1
- ChecksumBF3192CFF36023D3
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
M77744 EMBL· GenBank· DDBJ | AAA23749.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
M96793 EMBL· GenBank· DDBJ | AAB59065.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
U00096 EMBL· GenBank· DDBJ | AAC74175.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
AP009048 EMBL· GenBank· DDBJ | BAA35899.2 EMBL· GenBank· DDBJ | Genomic DNA | ||
M87040 EMBL· GenBank· DDBJ | AAA23741.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
Z11565 EMBL· GenBank· DDBJ | CAA77659.1 EMBL· GenBank· DDBJ | Genomic DNA |