TY - JOUR T1 - Macromolecular organization of the pyoverdine biosynthetic pathway in <em>Pseudomonas aeruginosa</em> JF - bioRxiv DO - 10.1101/438713 SP - 438713 AU - Véronique Gasser AU - Morgane Malrieu AU - Anne Forster AU - Yves Mély AU - Isabelle J Schalk AU - Julien Godet Y1 - 2018/01/01 UR - http://biorxiv.org/content/early/2018/10/19/438713.abstract N2 - The biosynthesis of the pyoverdine siderophore in Pseudomonas aeruginosa inlvolves multiple enzymes including Non-Ribosomal Peptide Synthetases (NRPS). We used in vitro single-molecule tracking and FRET–FLIM (Förster resonance energy transfer measured by fluorescence lifetime microscopy) to explore the spatial partitioning of the ornithine hydroxylase PvdA and to characterize its interactions with NRPS. The statistical description of thousands of single PvdA traces in cells using jump distance distribution analysis showed PvdA was mostly diffusing bound to large complex in the cytoplasm with a small exchangeable trapped fraction diffusing slower. FRET-FLIM clearly showed PvdA are physically interacting with the four NRPS PvdJ, PvdI, PvdL and PvdD of the pyoverdine pathway in the cellular context. Our data provide evidence for strongly organized multi-enzymatic biosynthetic complexes named siderosomes responsible for the siderophore biosynthesis. PvdA binding mode is strikingly different according to the NRPS it is interacting with suggesting PvdA binding site have co-evolved with the enzymatic active sites of NRPS. ER -