Fig. 2: Proposed biosynthesis of P. fluorescens MYb115 PKS cluster PfSgaAB-derived SLs. | Nature Communications

Fig. 2: Proposed biosynthesis of P. fluorescens MYb115 PKS cluster PfSgaAB-derived SLs.

From: Polyketide synthase-derived sphingolipids mediate microbiota protection against a bacterial pathogen in C. elegans

Fig. 2: Proposed biosynthesis of P. fluorescens MYb115 PKS cluster PfSgaAB-derived SLs.The alternative text for this image may have been generated using AI.

A Biosynthesis scheme of MYb115-derived PG-sphingolipids 4–6. The production of 3-ketodihydrosphinganines (KDSs) is catalysed by the iterative PKS (iPKS) PfSgaA and PLP-dependent serine palmitoyltransferase (SPT) PfSgaB. The reduction of KDSs to dihydrosphinganines 1–3 is presumably catalysed by the KDS reductase homologue PfSgaC. B PLP external aldimine formation following the addition of up to 10 mM L-serine (L-ser), monitored by UV–vis spectroscopy. External aldimine formation is signified by an increase in absorbance at 413 nm. C Schematic representation of PfSgaB-catalysed decarboxylative condensation between acyl-CoAs 7–9 and L-ser to give 3-ketodihydrosphinganines 10–12. D Relative activity of PfSgaB in the presence of C16-CoA 7 and L-serine, L-alanine or glycine, determined using the DTNB assay (412 nm). UV–vis measurements were recorded after 20 min of incubation. Error bars represent the standard deviation of three technical replicates. All measurements were corrected for non-specific background absorbance. E Extracted ion (EI) chromatograms of PfSgaB-derived products 10–12, detected by LC/ESI-MS. F [M + H]+ ions of PfSgaB-derived products 10–12, detected by LC/ESI-MS. The theoretical m/z is shown for each product.

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