Distribution of extrinsic proteins among various organisms as an index of evolution of oxygen-evolving PSII

摘要

Oxygen-evolving PSII complex contains different extrinsic proteins functioning to maintain its activity and stability among cyanobacteria, red algae and higher plants. Cyanobacterial and red algal PSIIs contain 33 kDa, 12 kDa proteins and cytochromec550 (cyt c550) as their extrinsic proteins (Shen et al. 1993, Enami et al. 1995), whereas PSIIs of green algae and higher plants contain the 33 kDa, 23 kDa and 17 kDa proteins (for review, see Seidler 1996). In addition, red algal PSII contains a unique 20 kDa protein (Enami et al. 1998). This implies that cyt c550 and the 12 kDa protein were replaced by the 23 kDa and 17 kDa proteins during evolution from cyanobacteria and red algae to green algae and higher plants, and the 20 kDa protein appeared during evolution from cyanobacteria to red algae and disappeared from red algae to green algae. The distribution of these extrinsic proteins among various organisms, therefore, provides a clue to elucidate the evolutionary process of the oxygen-evolving complex. In this study, we prepared the antibodies raised against the 20 kDa, 12 kDa proteins and cyt c550 from red algal PSII complex and examined their cross-reactivity with PSIIs and/or thylakoid membranes from cyanobacteria, red algae, diatom, brown algae, green algae and higher plants.