Inhibition of lanosterol 14 alpha-demethylase: Molecular modeling study of triazole derivatives acting against the phytopathogen Botrytis cinerea

Abstract

Botrytis cinerea is a phytopathogenic fungus that causes the gray mold disease. It isconsidered a main factor in post-harvest losses in fresh fruit crops, causing seriouseconomic losses in the agricultural industry. In addition, it has become an importantmodel for the molecular study of necrotrophic fungi. Although there are fungicides for itscontrol, many of them have failed since B. cinerea has evolved a variety of infectionmechanisms due to its genetic variability. In this regard, triazoles have been used for thecontrol of several pathogenic fungi. These compounds act as inhibitor of the lanosterol14 alpha-demethylase, a cytochrome p450 (CYP54B)-dependent enzyme systeminvolved in the synthesis of ergosterol.In order to explain the biological behavior of different CYP54B-triazole complexes weperformed a combined molecular modeling study. In this way, we determined theconformational aspects of the currently available triazole antifungal agents whencomplexed with CYP54B. Furthermore, a new series of novel triazole derivatives wassynthesized and their inhibitory activity was assessed. Some of them showed stronginhibitory effects comparable to that observed for commercial antifungal drugs. Themolecular modeling study was carried out in three stages. First, we conducted moleculardocking calculations. Next, we performed molecular dynamics (MD) simulations and freeenergy of the different complexes was calculated. Finally, we performed a per-residueanalysis in order to identify the amino acids involved in the intermolecular interactions ofthe complexes.Our molecular modeling study indicated that all active compounds are bounded in asimilar spatial arrangement. Thus, it is reasonable to assume that the compoundsstudied here interact with the same region of the enzyme. MD simulations enable us toexplain the different activities displayed by these compounds. The main stabilizinginteractions are Tyr101, Thr105, Tyr115, Phe208, Ala287, His290 and Ile353.