Timecourse transcriptomics of S. ambofaciens ATCC 23877 pirin defective strain

Pirins are evolutionarily conserved iron-containing proteins that are found in all kingdoms of life, and have been implicated in diverse molecular processes, mostly associated with cellular stress. In the present study we started from the evidence that in spiramycin-producing strain Streptomyces ambofaciens ATCC 23877 insertional inactivation of pirin-like gene SAM23877_RS18305 (pirA) by ?C31 Att/Int system-based vectors resulted in marked effects on central carbon and energy metabolism gene expression, high sensitivity to oxidative injury and repression of polyketide antibiotic production. By using integrated transcriptomic, proteomic, metabolomic profiling, and genetic complementation we show that most of these effects could be traced to inability of the pirA-defective strain to modulate beta-oxidation pathway leading to unbalanced supplying of precursor monomers for polyketide biosynthesis. Indeed, in silico protein-protein interaction modeling and in vitro experimental validation allowed us to demonstrate that PirA is a novel redox-sensitive negative modulator of very long chain acyl-CoA dehydrogenase catalyzing the first committed step of the beta-oxidation pathway.