Duplication and divergence of the Psb27 subunit of Photosystem II in the green algal lineage

Abstract

Photosystem II (PSII) is subject to light-induced damage and continuously undergoes repair to restore the damaged photosystcms. During repair of PSII, the Psb27 protein interacts with the CP43 subunit of PSII. Two Psb27-like proteins (Psb27-H 1 and Psb27-H2) are involved in the repair of PSII in the higher plant Arabidopsis thaliana. Here, we present evidence that duplication and divergence of Psb27 occurred in the green algal lineage and that the Psb27-H2 protein shares c. 30% sequence identity with Psb27-H 1. Structural modelling of Arabidopsis thaliana Psb27-H 1 and Psb27-H2 indicate that the two proteins have different distributions of surface charge. We suggest that the green algal lineage Psb27-H2 protein occupies a different binding niche than does Psb27-H 1. © 2014 The Royal Society of New Zealand.