ACP is a central component of fatty acid synthesis (FAS) in E. coli, serving as a scaffold for acyl chain elongation. It shuttles intermediates between enzymes (e.g., acetyl-CoA carboxylase, β-ketoacyl-ACP synthases) and facilitates interactions with regulatory proteins like SpoT, which modulate (p)ppGpp synthesis under stress .
The O8 serotype is defined by its mannose homopolymer O-antigen, synthesized via the ABC transporter pathway. This process involves conserved and serotype-specific mannosyltransferases (WbdC, WbdB, WbdA) .
While no studies explicitly target O8 acpP, recombinant ACPs from other species (e.g., Ralstonia, Pseudomonas) have been expressed in E. coli to study fatty acid or polyhydroxyalkanoate (PHA) synthesis .
| ACP Source | Host Strain | Complementation Efficiency | Key Observations |
|---|---|---|---|
| Ralstonia | CY1877 (acpP−) | Partial (AcpP1 only) | AcpP1 supports growth; others fail |
| Pseudomonas | K1060 (LacIq) | Successful PHB production | Requires strong promoters |
The O8 O-antigen and ACP pathways are distinct, but lipid A (synthesized via LpxD, which interacts with ACP ) and lipid-linked intermediates (e.g., undecaprenyl pyrophosphate) may intersect. For example:
Lipid A Synthesis: ACP interacts with LpxD, linking fatty acid synthesis to lipopolysaccharide (LPS) assembly .
Metabolic Burden: Recombinant protein expression (e.g., AAR, PHA synthases) impacts fatty acid pathways, as shown in E. coli M15 and DH5α strains .
O8-Specific ACP Engineering: No studies have targeted acpP from O8 strains. Potential applications include enhancing fatty acid derivatives for O-antigen or lipid A modifications.
Synthetic Biology: Tandem ACP constructs (e.g., di- or tri-domain ACPs ) could improve substrate shuttling in O8 mutants.
Stress Adaptation: ACP-SpoT interactions modulate (p)ppGpp levels under amino acid starvation , a mechanism exploitable in recombinant systems.
KEGG: ecr:ECIAI1_1129