Figure 3.
EPR spectra of A549 cells after their 1 h incubation with (a) 5.5 μM and (b) 0.5 μM sRL2 (molar ratio of spin label 1 to RL22: 4) acquired at different time points after the incubation. The zero time point corresponds to the start of EPR spectra acquisition. Initial spin concentrations observed by EPR at the zero time point for these two samples were 730 μM (a) and 60 μM (b). The spectra were acquired at 35 °C with the following parameters: microwave frequency (a) 9.236816 GHz, (b) 9.233912 GHz; (a,b) microwave power 2.0 mW; conversion time (a) 30.89 ms, (b) 19.54 ms; sweep time (a) 15.82 s, (b) 10.00 s; time constant (a) 40.96 ms, (b) 20.48 ms; (a,b) 512 points; the number of scans (a) 16 or (b) 64. In both cases, the external magnetic field was modulated at frequency 100 kHz and modulation amplitude 0.2 mT.