Article Binding Sites Chlorophyll Electron transfer Exciplex Femtosecond absorption spectroscopy Hydrogen Bonding Molecular Conformation Mutation Photosynthesis Photosystem I Protein Complex Primary charge separation Principal Component Analysis Principal component analysis Spectrophotometry Synechocystis Water absorption spectroscopy adiabaticity amino acid analysis amino acid substitution bacterial strain binding site chemistry chlorophyll chlorophyll 2A chlorophyll 2B conformation controlled study electron transport