Redox process is crucial for inhibitory properties of aurintricarboxylic acid against activity of YopH: virulence factor of Yersinia pestis

Kuban-Jankowska, Alicja; Sahu, Kamlesh K; Niedzialkowski, Pawel; Gorska, Magdalena; Tuszynski, Jack A; Ossowski, Tadeusz; Wozniak, Michal

Cyclic voltammetry (CV) experiments were performed using an Autolab potentiostat/galvanostat (model PGSTAT30) supported by the GPES software. The experiments were performed at room temperature in DMSO solution with 0.1 M tetrabutylammonium tetrafluoroborate (TBAP) as the supporting electrolyte, at a scan rate of 100 mV/s under argon atmosphere or in the oxygen-saturated DMSO solution. A conventional three-electrode configuration consisting of a glassy carbon electrode (GC), a working electrode with a 3-mm diameter. The platinum wire used as the counter electrode and an Ag/AgCl in 3M KCl reference electrode were used, respectively. Each time before use, the working GC was polished with Al 2 O 3 powder on a wet pad, then the electrode was washed with nanopure water, and dried under a stream of nitrogen. The oxygen-saturated DMSO solution used to perform measurement was obtained by the procedure described in the literature [26] . The concentration of oxygen in oxygen-saturated DMSO at 298 K was 2.2 · 10 -3 M [27] . During all the experiments with oxygen the air was carefully excluded from the measurement cell and the oxygen was bubbled directly into the cell in order to obtain desirable concentration. The error in oxygen concentration of all measurement is estimated to be approximately 1%. The oxygen flow was adjusted by a mass flow controller (HiTec, Bronkhorst).