Light-induced intracellular hydrogen peroxide generation through genetically encoded photosensitizer KillerRed-SOD1

AbstractHydrogen peroxide (H2O2) plays an important role in various biological processes in numerous organisms. Depending on the concentration and the distribution within the cell, it can act as stressor or redox signalling molecule. To analyse the effects of H2O2 and its diffusion within the cell we developed the new genetically encoded photosensitizer KillerRed-SOD1 which enables a light-induced spatially and temporally controlled generation of H2O2 in living cells. The KillerRed-SOD1 is a fusion protein of the photosensitizer KillerRed (KR) and the cytosolic superoxide dismutase isoform 1 (SOD1) connected by a helix-forming peptide linker. Light irradiation at a wavelength of 560 nm induced superoxide radical formation at the KR domain which was transformed to H2O2 at the SOD1 domain. H2O2 was specifically detected under live cell conditions using the fluorescent sensor protein HyPer. Genetically encoded photosensitizers have the advantage that appropriate tag sequences can determine the localisation o...