Modeling The Mechanism Of Efflux-dysfunction Mutation E574K Of Yeast Pdr5p Protein With Molecular Docking

In recent years, due to the substantial increase of organ transplant cases, cancer chemotherapy and extensive use of broad-spectrum antibiotics, etc., the risk of fungal infection has increased year by year and become the main cause of death in many diseases. At the same time, the extensive use of antifungal drugs has also made the fungal resistance growing, which brought great challenges for clinical treatment. The ABC transporters can mediate the efflux of a variety of drugs, which is the main reason for multidrug resistance of fungi, and also leads to the decrease of curative effect. At present, the efflux mechanism of fungal transporters is not very clear, thus increasing the difficulty of drug design.In this study, the yeast transmembrane protein Pdr5p was used as the research object. Pdr5p has a high similarity in structure and function to Candida albicans and ABC transporters related to mammalian drug tolerance, so it is an ideal research object. Moreover, studies have shown that certain site-directed mutagenesis at the end of transmembrane helix could disrupt the transport activity of Pdr5p. According to the experimental results of our collaborative laboratory, two novel mutants, E574K and E580K, remained hypersensitive to all tested Pdr5p substrates without affecting their protein expression levels, localization or ATPase activities. In order to further explain the principle between the phenomenon, we used bioinformatics tool, molecular docking, to simulate the binding of Pdr5p and all the substrates. It was found that the E574K mutation could destroy the hydrogen bond and electrostatic interaction between Pdr5p and the substrates, and interfere the binding of substrates to the receptor active site. E580K mutation E580K might block the substrate transit channel by interfering the substrates recognition process of Pdr5p. Both E574 and E580 are located on TMH2, proving that TMH2 plays an important role in drug efflux.Biology experimental methods and bioinformatics calculation methods are based on different principles and strategies, they are very complementary. And in recent years, with the development of their respective technologies, these two methods are more and more mixed. Computing can save costs and time for experiments, and experiments can modify and optimize computational methods and strategies. The combination of the two methods not only can help us to better understand some biological problems, but also can provide guidance for rational drug design. The broad application of the combination is waiting us to explore.