A new bacterial phospholipase D with specificity for phosphatidylethanolamine over phosphatidylcholine

Phospholipases D (PLDs) are key enzymes involved in numerous processes in all living organisms. PLD catalyzes, notably, the hydrolysis of different phospholipids (PLs) generating phosphatidic acid (PA). PA is an important moiety at the crossroads of multiple metabolic pathways and it is involved in signaling reactions, cancer genesis in mammals, bacterial infections and the defense response in plants. In current study, searching for a plant-like PLD in microbes, a new PLD has been identified in the bacterium Dechloromonas aromatica RCB that had been previously isolated from polluted soil. Here we have recombinantly expressed and characterized this particular PLD which shares common enzymatic features with classical PLDs from plants and bacteria regarding pH and temperature. However, compared to these already known PLDs, this PLD from D. aromatica has a strong preference for phosphatidylethanolamine (PE) over all other PLs, especially phosphatidylcholine (PC). Moreover, we showed that this PLD has a typoselectivity for unsaturated PE that does not exist for PC. Interestingly, the recombinant expression of this new bacterial PLD led to a stunning change in PL composition and amount in E. coli, especially for PA. These findings offer new perspectives on PA production and regulation in bacteria.