Figure 2.

Room-temperature EPR spectra of tyrosyl radicals D⋅ and Z⋅ in Cl⁻-depleted PSII-2 (A) and PSII-3 (B). Spectra were recorded in the absence (dotted lines) or presence (solid lines) of 4 mM methylamine-hydrochloride. In both A and B, spectra with larger amplitudes were recorded under illumination and correspond to D⋅ and Z⋅; spectra with smaller amplitudes were recorded in the dark after illumination and correspond to D⋅.