Polyvalent metal ions (fungal enzyme cofactors)

Polyvalent metal ions, such as iron (Fe2+/3+), zinc (Zn2+), copper (Cu2+), and manganese (Mn2+), are indispensable inorganic elements that function as essential cofactors for numerous fungal enzymes (Gerwien et al., 2018). These ions facilitate critical biochemical reactions, including DNA replication, mitochondrial respiration, and the detoxification of reactive oxygen species (Hood and Skaar, 2012). Because fungi cannot synthesize these metals de novo, they must scavenge them from the host environment using specialized acquisition systems like siderophores and high-affinity transporters (Potrykus et al., 2014). The availability of these metals is a key determinant of fungal growth and virulence within the host. Therapeutic targeting of these ions typically involves chelation therapy, which sequesters the metals to deprive fungal enzymes of their necessary cofactors, effectively halting fungal growth (Subissi et al., 2010). For example, the antifungal drug ciclopirox works by chelating polyvalent cations like Fe3+ and Al3+, leading to the inhibition of metal-dependent enzymes such as cytochromes and catalases. However, the primary challenge in targeting these ions is achieving selectivity, as the host also relies on the same polyvalent metals for vital physiological processes. Consequently, systemic use of broad-spectrum chelators can lead to toxicity and interference with host metalloenzymes. Despite these challenges, understanding metal homeostasis remains a fertile ground for developing novel antifungal strategies that exploit the unique metal requirements of pathogens.

Other names

Essential metal ionsDivalent metal cationsMetal cofactorsTrace elementsInorganic enzyme cofactors

Chelation of essential polyvalent metal cations resulting in the inhibition of metal-dependent enzymes and disruption of fungal cellular metabolism.