National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Study of the differences in the architecture of the binding pockets of two major MDR pumps of yeast Saccharomyces cerevisiae, Pdr5p and Snq2p, using their common substrates
Backová, Lenka ; Gášková, Dana (advisor) ; Krůšek, Jan (referee)
Multidrug resistance (MDR) is responsible for the decrease in drug effectiveness on pathogenic microorganisms or tumours. One of the mechanisms of multidrug resistance is drug transport out of the cell (efflux) by membrane transporters - pumps. Main MDR pumps of a yeast species Saccharomyces cerevisiae are Pdr5p and Snq2p, who share high amino acid sequence identity. This thesis focuses on the differences of these pumps, their binding pockets and their arrangement. The binding pocket of Pdr5p is better researched and comparing the results with those of pump Snq2p leads to broader knowledge about the binding pocket of Snq2p. We use disc diffusion assay to determine common substrates of both pumps, ketoconazole and bifonazole. These substrates are used in potentiometric fluorescent probe diS-C3(3) assay. Results of these experiments lead us to the findings that the binding pocket of Snq2p has multiple binding sites. Binding pockets of pump Pdr5p and Snq2p differ in binding sites and their conformation. However, the conformation of both pumps is dynamic, which has been shown after the addition of glucose to supply the pumps with energy. 1
Study of the performance of microbial MDR pumps by fluorescent probes: effect of potential inhibitors
Kodedová, Marie ; Gášková, Dana (advisor) ; Höfer, Milan (referee) ; Sychrová, Hana (referee)
The current increased use of antifungal agents has resulted in the development of resistance to these drugs. Search for new antifungals with different mechanisms of action overcoming the multidrug resistance is thus underway. Surface-active antifungals have the advantages of minimizing host toxicity and the emergence of drug resistance. We have developed a fluorescence method based on the use of the potentiometric fluorescent probe diS-C3(3), substrate of two major S. cerevisiae MDR pumps, Pdr5p and Snq2p. It allows us to monitor with high sensitivity and in real time changes in the activities of both pumps and also in membrane potential. We present here an efficient strategy for identifying pump inhibitors with minimal side effects on membrane integrity, and compare the potencies of different inhibitors towards MDR pumps. New efficient inhibitors of MDR pumps could potentially be used in conjunction with current antimicrobials that are MDR pump substrates. The method can be also used to determine the mechanism of action of surface-active drugs and their lowest effective concentrations.

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