Abstract
Oxygen-evolving PSII preparations isolated from different plant species contain different extrinsic proteins. We have examined the cross-reactivity of PSII and/or thylaloid membranes from various organisms with antibodies raised against the higher plant (H) 23 and 17 kDa proteins and the red algal (R) 20, 12 kDa proteins and cytc550. In the 2002 Annual Meeting of JSPP, we reported that thylakoid membranes from brown algae and diatoms cross-reacted with anti-R20 and anti-Rc550, while PSIIs or thylaloid membranes from a green alga cross-reacted with anti-H 23. In this study, cross-reactivities of thylakoid membranes from Haptophyta and Prasinophyceae or Euglena PSII with these antibodies were examined. The results showed that Haptophyta cross-reacted with anti-R20 and anti-Rc550, and Prasinophyceae and Euglena with anti-H 23. These suggest that red algal extrinsic proteins have been conserved in brown algae, diatoms and Haptophyta appeared by secondary endosymbiosis of red algae
