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Decoding resistance in Diutina catenulata by validating clinically relevant Erg11/Fks1 mutations
Wei Zhang1,2,3, Na Wang1, Xin-Fei Chen3
1Hebei Key Laboratory of Pathogenic Mechanisms and Diagnosis & Treatment Technologies for Lung Microbiome, The First Affiliated Hospital of Hebei North University, Zhangjiakou, Hebei, China.
Objective:
To verify the causal relationship between specific mutations in the ERG11 and FKS1 genes and antifungal drug resistance in clinical isolates of Diutina catenulata.
Methods:
Recombinant plasmids expressing mutant alleles of ERG11 (F126L, K143R) or FKS1 (F621I, S1123G, I1348S, and the triple mutant S625L/S1123G/F1354L) were constructed and functionally validated in a Saccharomyces cerevisiae W303-1a model. Susceptibility testing was performed under different nutrient conditions (SD-Ura and YPD). Molecular docking analysis was conducted to elucidate the structural mechanisms of resistance.
Results:
Functional validation in S. cerevisiae confirmed that both ERG11 and FKS1 mutations conferred resistance in a nutrient-dependent manner. The ERG11-F126L mutation increased the fluconazole MIC by 21-fold in SD-Ura compared to YPD. FKS1 mutations led to 1.4 to 2-fold increases in echinocandin MICs. Molecular docking revealed the mechanistic bases: ERG11-F126L expanded the ligand-binding cavity (ΔΔG +1.2 kcal/mol), FKS1-F621I disrupted hydrophobic interactions, and compound mutations synergistically perturbed ATP-binding domains.
Conclusion:
Specific mutations in ERG11 (F126L, K143R) and FKS1 (F621I and hotspot variants) are the primary drivers of the pronounced antifungal resistance observed in Chinese D. catenulata strains, with resistance phenotypes being modulated by nutrient availability.
Insights
Specific mutations in the ERG11 and FKS1 genes cause antifungal drug resistance in Diutina catenulata. This resistance is nutrient-dependent, impacting treatment strategies for this fungal pathogen.
Area of Science:
- Mycology
- Molecular Biology
- Drug Discovery
Background:
- Diutina catenulata is an emerging fungal pathogen.
- Antifungal drug resistance is a growing clinical concern.
- Understanding resistance mechanisms is crucial for effective treatment.
Purpose of the Study:
- To investigate the causal link between ERG11 and FKS1 gene mutations and antifungal drug resistance in Diutina catenulata.
- To elucidate the structural basis of resistance through molecular docking.
Main Methods:
- Constructed and validated recombinant plasmids with mutant ERG11 and FKS1 alleles in Saccharomyces cerevisiae.
- Performed antifungal susceptibility testing under varying nutrient conditions (SD-Ura, YPD).
- Utilized molecular docking to analyze drug-target interactions and resistance mechanisms.
Main Results:
- ERG11 (F126L) and FKS1 mutations conferred significant antifungal resistance in a nutrient-dependent manner.
- ERG11-F126L increased fluconazole MIC 21-fold in SD-Ura medium.
- FKS1 mutations increased echinocandin MICs by 1.4-2 fold; molecular docking revealed altered binding cavities and disrupted interactions.
Conclusions:
- Specific ERG11 and FKS1 mutations are key drivers of antifungal resistance in Chinese D. catenulata strains.
- Nutrient availability modulates the observed resistance phenotypes.
- Findings provide insights into resistance mechanisms for targeted antifungal therapy.
