Pseudomonas quinolone signal–iron(III) complex (PQS-Fe(III))

The Pseudomonas quinolone signal–iron(III) complex is a critical mediator of virulence and nutrient acquisition in the opportunistic pathogen Pseudomonas aeruginosa (Diggle et al., 2007). PQS (2-heptyl-3-hydroxy-4-quinolone) is a quorum-sensing molecule that binds ferric iron (Fe3+) with high affinity, forming a complex that facilitates iron uptake and regulates the expression of numerous virulence factors, including pyocyanin and elastase (Bredenbruch et al., 2006). This complex interacts with the transcriptional regulator PqsR (also known as MvfR) to coordinate population-wide behaviors such as biofilm formation and host tissue degradation (Rampioni et al., 2016). Because iron is essential for bacterial survival and PQS is unique to Pseudomonas, the PQS-iron complex and its biosynthetic pathway are attractive targets for anti-virulence therapies. Strategies to disrupt this system include the use of iron mimetics like gallium, which replaces iron in the complex to render it non-functional, or small molecule inhibitors that prevent PQS synthesis or binding (Goss et al., 2018). Targeting this complex offers a way to attenuate bacterial pathogenicity without imposing the strong selective pressure associated with traditional bactericidal antibiotics.

Other names

2-heptyl-3-hydroxy-4-quinolone-iron complexPQS-iron complexPQS-Fe complexPseudomonas quinolone signal-iron complex

Competitive inhibition of iron acquisition and quorum sensing signaling by disrupting the formation or function of the PQS-iron complex.