Diversity in Structure and Function: How Cyanobacterial Metallophores Reveal a Broadening Perspective of Microbial Metal-Chelators

Cyanobacteria are known for their rich secondary metabolome with a long history of research directed toward the industrial and pharmaceutical applications of their natural products. Cyanobacterial metallophores (metal-chelating molecules), however, are understudied relative to metallophores from other phyla despite evidence suggesting that genes for metallophore biosynthesis are well-represented in cyanobacterial genomes. Many of the characterized cyanobacterial metallophores are formed from hybrid biosynthetic pathways and feature mixed coordinating functional groups, leading to enhanced structural and functional diversity. The few characterized metallophore families have intriguing properties including promiscuity of metal binding, photoreactivity, and amphiphilicity that are yet to be fully explored. Research suggests that these compounds are ecologically relevant and could guide community dynamics by controlling the availability of iron, detoxifying copper, and allelopathically inhibiting certain organisms. Cyanobacterial metallophores also have potential in the fields of therapeutic design, bioremediation, technology, and agriculture. In the past five years, the number of characterized metallophores from cyanobacteria has doubled, pointing to the great promise for future discoveries.