A cryptic long-chain 3-ketoacyl-ACP synthase in the Pseudomonas putida F1 unsaturated fatty acid synthesis pathway

Abstract

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Divergent unsaturated fatty acid synthesis in two highly related model pseudomonads

“…When the P. putida F1 fabA was replaced by E. coli fabA expression of E. coli FabA plus P. putida F1 FabB completely rescued growth of the ∆ desA ∆fabA strain with IPTG induction (Figure 7). However, when the P. putida F1 fabA plus fabF2 plasmid was used to complement the P. putida F1 ∆ fabA ∆desA strain growth was restored only upon induction with IPTG (Figure 8a) indicating that FabF2 was less active than FabB in UFA synthesis as previously observed (Dong et al, 2021). When the P. putida F1 fabA of the fabA plus fabF2 plasmid strain was replaced by E. coli fabA , this construct allowed weak growth even in the absence of IPTG induction (Figure 8b).…”

“…There are two major mechanisms to synthesize UFAs in bacteria: an oxygen‐dependent fatty acid desaturation pathway and the FabAB pathway. P. putida F1 differs from P. aeruginosa PAO1 in that its aerobic desaturation pathway fails to compensate for the loss of the FabAB pathway even when DesA is overexpressed (Dong et al, 2021). This argues that the lack of compensation is not the fault of the P. putida F1 DesA protein but of a component of the electron transfer process that is only weakly active.…”

“…The internal deletion strain of fabA was obtained by screening on LB sucrose plates containing kanamycin, then verified by PCR and sequencing. The fabA fabF2 double mutant was constructed by the same procedures using the strain expressing fabF2 (Dong et al, 2021) as the template.…”

Functional Amyloids in Pseudomonas aeruginosa Are Essential for the Proteome Modulation That Leads to Pathoadaptation in Pulmonary Niches

“…The “CF-selected proteins” Fab, Acc, and OprL, which facilitate integrity-mediated fitness in the CF lung environment, were upregulated in PAO1 pFap ( 53 ). Attached PAO1 pFap showed upregulation of FabF1, which is responsible for appendages and membrane fluidity, and KdsC, which is essential for liposaccharide production responsible for cellular integrity ( 54 , 55 ). A protease, PA3611, was 10-fold upregulated in PAO1 pFap biofilm, which is associated with lung inflammation and bronchial fibrosis ( 56 ).…”

Mechanism-based cross-linking probes capture the Escherichia coli ketosynthase FabB in conformationally distinct catalytic states

“…Aerobic and anaerobic pathways can also coexist, as is the case for P. aeruginosa, which can utilize the anaerobic FabA/FabB route or one of two aerobic membrane desaturases (Zhu et al, 2006). Additionally, the FabF/FabB dichotomy is not strictly conserved and there are several FabF orthologs that are capable of complementing E. coli fabBknockout cell lines and FabB orthologs capable of extending C16:1 to C18:1 (Morgan-Kiss & Cronan, 2008;Zhu et al, 2009;Wang & Cronan, 2004;Luo et al, 2016;Li et al, 2016;Dong et al, 2021). Therefore, the metabolic and genetic background of a particular bacterial species may dictate the selective pressure to maintain specific FabB structural elements that allow the recognition and extension of the cis-3-decenoyl-ACP substrate.…”