Figure 5.

Effect of light quality on the sensitivity of LHCII protein phosphorylation to NEM in thylakoid membranes isolated from highlight-illuminated pumpkin leaves. Isolated thylakoids were phosphorylated in PSII light or in white light (WL) for 20 min in the presence or absence of 0.1 mm NEM. In the experiment indicated as PSII light + NEM → WL + NEM, the thylakoids were first phosphorylated in PSII light with NEM for 5 min, and subsequently, the PSII light was turned off and white light on. The phosphorylation was then continued for 15 min in white light. Phosphorylation level of LHCII proteins was identical in control assays without NEM, regardless of whether the activation of the kinase occurred in white light or in PSII light. The phosphorylation level of LHCII proteins was determined as described in Figure 1, and the immunoblots were quantified by scanning. Results are means ± se, n = 2.