Figure 2.

Photochemical activity of RCII complexes. The light-induced accumulation of P680⁺ (A) and Pheo⁻ (B) in two preparations isolated from the CP47-less strain expressing His-tagged D2 protein. The preparations differed in the content of PSI (red circles, sample analyzed in Figure 1C; green squares, sample analyzed in Supplemental Figure S5), and in a pea 5-Chl reaction center complex isolated using Cu affinity chromatography (black diamonds). Accumulation of P680⁺ (A) and Pheo⁻ (B) was elicited by strong red actinic light (wavelength 660 nm, 1,000 µmol photons m⁻² s⁻¹) in the presence of silicomolybdate (electron acceptor) or sodium dithionite (electron donor), respectively. The curves were normalized to the same absorption value of the preparations at the red Qy absorption maximum of Chl.