CYP51 Inhibitors in Fungal Drug Discovery

The cytochrome P450 enzyme CYP51, also known as lanosterol 14α-demethylase, catalyses a pivotal step in the ergosterol biosynthetic pathway of fungi. Inhibition of CYP51 leads to depletion of fungal membrane sterols and accumulation of toxic intermediates, making it an enduring target for antifungal drug development. Azole compounds, which coordinate to the haem iron of CYP51, remain the clinical mainstay for the treatment of a broad spectrum of fungal infections in humans and plants. However, rising incidence of resistance—driven by point mutations in the enzyme’s active site and overexpression of efflux systems—has spurred efforts to discover novel scaffolds, enhance binding affinity, and circumvent cross‐resistance. Recent advances integrate high‐resolution structural biology, computational design and medicinal chemistry to optimise both azole derivatives and non‐azole inhibitors. Fragment‐based screening, molecular dynamics simulations and substrate analogues have elucidated key binding interactions and phylum-specific pockets, guiding the rational design of next‐generation antifungals with improved selectivity and pharmacokinetic profiles. Beyond human health, CYP51 inhibitors are also essential in agricultural settings to protect crops against phytopathogens while minimising environmental impact.

Research from Nature Portfolio

Recent studies have probed the molecular basis of triazole resistance through structural interrogation of clinically relevant mutations in fungal CYP51. High‐resolution crystal structures of Saccharomyces cerevisiae lanosterol demethylase harbouring conserved tyrosine‐to‐phenylalanine and tyrosine‐to‐histidine substitutions reveal disruption of a water-mediated hydrogen bond network that is critical for coordination of short-tailed azoles such as fluconazole and voriconazole. These findings demonstrate that single amino acid changes in the active site can differentially impair binding of triazole subclasses, suggesting avenues to design inhibitors that retain potency against resistant strains. The work underscores the importance of integrating structural insights with mutational data to predict resistance trajectories and to engineer compounds capable of overcoming emerging drug-resistance mechanisms.

CYP51 Inhibitors in Fungal Drug Discovery publication trend

The graph below shows the total number of articles in cyp51 inhibitors in fungal drug discovery across all publications each year (not limited to Nature Index journals).

Technical terms

CYP51 (lanosterol 14α-demethylase): A cytochrome P450 enzyme catalysing removal of the 14α-methyl group in sterol biosynthesis, essential for fungal membrane integrity.

Azoles: A class of antifungal compounds containing an imidazole or triazole ring that coordinate to the haem iron of CYP51, blocking ergosterol formation.

Ergosterol: The principal membrane sterol in fungi, analogous to cholesterol in mammals, whose depletion compromises cell viability.

Minimum inhibitory concentration (MIC): The lowest concentration of an antifungal agent required to inhibit visible growth of a microorganism in vitro.

Resistance mutation: A genetic alteration in CYP51 that reduces inhibitor binding, often through changes in active-site residues or hydrogen-bond networks.

Binding affinity (K_d): A measure of the strength of interaction between an inhibitor and its target enzyme, with lower values indicating tighter binding.

References

1. The Fungal CYP51s: Their Functions, Structures, Related Drug Resistance, and Inhibitors. Frontiers in Microbiology (2019).
2. Structural and Functional Elucidation of Yeast Lanosterol 14α-Demethylase in Complex with Agrochemical Antifungals. PLOS ONE (2016).
3. Triazole resistance mediated by mutations of a conserved active site tyrosine in fungal lanosterol 14α-demethylase. Scientific Reports (2016).
4. Structural analyses of Candida albicans sterol 14α-demethylase complexed with azole drugs address the molecular basis of azole-mediated inhibition of fungal sterol biosynthesis. Journal of Biological Chemistry (2017).
5. Structural complex of sterol 14α-demethylase (CYP51) with 14α-methylenecyclopropyl-Δ7-24, 25-dihydrolanosterol. Journal of Lipid Research (2011).
6. Small‐Molecule Inhibitors Targeting Sterol 14α‐Demethylase (CYP51): Synthesis, Molecular Modelling and Evaluation Against Candida albicans. ChemMedChem (2020).