Ectopic Expression of Full Length D1 Protein and Factors Limiting Photosystem II (PSII) Repair in Synechocystis Sp. PCC6803

Abstract

The research was originally conceived as a study on the role of N-terminus of D1 protein of the photosystem II complex. It was hypothesized that the N-terminus is required for the turnover of D1 protein, which is a repair process that maintains photosynthetic function. A SYNECHOCYSTIS sp.PCC6803 mutant was constructed that allows to study N-terminal mutation to test the hypothesis that the exposed N-terminus is needed for the action of FtsH protease in the process of degradation of the damaged D1 protein in Photosystem II repair process (Chiba et al., 2000, EMBO Reports 1, 47-52). During the course of these experiments, we observed that the constructs displayed impaired D1 repair even with the wild type amino acid sequence. This led to test the hypothesis, that the transcript levels restrict the rate of repair. To test this hypothesis is the major part of the thesis project. The experimental data suggests that the rate of repair of D1 protein is proportional to the psbA transcript levels.