By Dr Paul Roepe, Professor & Co-Director, Georgetown University Center for Infectious Disease, Georgetown University
This seminar will describe chemical biology and biochemical approaches for elucidating the molecular mechanisms of antimalarial drug resistance phenomena, particularly for quinoline - and endoperoxide - based antimalarial drugs. For example, combining drug probe syntheses with live cell microscopy and other techniques has been central to our work for many years. First, work with chloroquine probes will be reviewed quickly. More recently, capitalizing on characterization of coumarin - based fluorescent glutathione probes, we have synthesized less expensive and more convenient redox probes in this class including interesting morpholino derivatives and dextran conjugates, and have begun to quantify their localization and intensity within live malarial parasites. Synthesis of fluorescent antimalarial drug probes, in particular "NBD-chloroquine" and "NBD-piperaquine" have allowed detailed analyses of drug transport, and azidoperfluorophenyl "tagged" drug probes have allowed us to map drug binding sites for purified proteins. These experiments and additional approaches for elucidating the structure and function of antimalarial drug resistance proteins such as PfCRT will be summarized.