Figure 6. PsbO bound to PSII is protected against degradation by native proteases.

PSII membrane fragments from spinach were isolated and incubated for 5 h in the absence (PSII) or the presence (PSII_red) of reduced thioredoxin, either with no protease or with rHhoA, rHhoB, or rHtrA. After SDS-PAGE, the proteins were blotted and immunostained using an antibody directed against PsbO. Small arrows indicate PsbO degradation fragments (F1 to F4).