Metal complexes with valuable biomolecules produced by Pseudomonas aeruginosa: a review of the coordination properties of pyocyanin, pyochelin and pyoverdines

Pseudomonas aeruginosa is an opportunistic, Gram-negative bacterium, involved in severe infections associated with cystic fibrosis, pneumonia, burn wounds, ocular diseases, and immunosuppressive illnesses, and is a major cause of intrahospital infections. This bacterium is also one of the most commercially and biotechnologically significant microorganisms, since it can produce valuable biomolecules which represent a rich source of potential drug candidates. On the other hand, metal complexes have been used in medicine for both therapeutic and diagnostic purposes since ancient times. This class of compounds can adopt different geometries and generally have a three-dimensional shape, contributing to their higher clinical success compared to flat purely organic compounds. In the present review article, attention has been devoted to the three natural products derived from P. aeruginosa, namely pyocyanin, pyochelin, and pyoverdine(s) and their ability to form complexes with different metal ions, including iron(ii/iii), manganese(ii/iii), gallium(iii), chromium(iii), nickel(ii), copper(ii), zinc(ii) and cadmium(ii). Investigation of the coordination properties of pyocyanin, pyochelin, and pyoverdine(s) towards these metal ions is important because the resulting bacterially derived natural product-metal complex can serve as a model for the study of metal ion metabolism (transport and storage) in living systems and might also be considered as a novel therapeutic agent for potential use in medicine.