β -cyclopiazonic acid binds iron demonstrating siderophore-like activity and promotes growth in Pseudomonas aeruginosa

This chemical study reports a novel siderophore-like compound, β -cyclopiazonic acid ( 1 , β -CPA) extracted from marine fungus Aspergillus flavus . The chemical structure of β -CPA was elucidated by a combination of extensive spectroscopic analyses and TDDFT-ECD calculations. The iron-binding ability and CAS assays demonstrate that β -CPA is a novel siderophore that features a different chemical structure from those of traditional siderophores. The β -CPA has no obvious influence on the growth of bacterium Pseudomonas aeruginosa PAO1. However, its iron chelator could promote the growth of P. aeruginosa PAO1, suggesting that P. aeruginosa employed siderophores to sequester iron, which is vital for their survival. The study provides the physiochemical evaluation of β -CPA, an unusual skeleton-structure siderophore, which for the first time, was proven to have the ability to bind iron and affect P. aeruginosa growth. This new discovery of siderophore provides an opportunity for developing novel anti- P. aeruginosa drugs.