Identification of phasin PhaF interaction partners and proteomic analysis of polyhydroxyalkanoate granules in Pseudomonas putida

Phasin PhaF is a multifunctional protein associated with the surface of polyhydroxyalkanoate (PHA) granules (carbonosomes) that contributes significantly to PHA biogenesis in pseudomonads. PhaF participates in PHA granule stabilization and segregation and its deletion has a notable impact on overall transcriptome, PHA accumulation and cell physiology, suggesting a more extensive function than simply being a simply granule structural protein. We followed a systematic approach to detect potential interactions of PhaF with other components of the cell, which could pinpoint unexplored functions of PhaF in the regulation of PHA production. We determined the PhaF interactome in Pseudomonas putida KT2440 using pull-down-mass spectrometry (PD-MS), in which proteins interacting with PhaF were determined. We separately determined the PHA granule proteome (all proteins associated with PHA granules) in Pseudomonas putida KT2440 using two granule preparation methods.