Photosynthetic bacteria do not release oxygen during photosynthesis but can convert solar energy into chemical energy with remarkably high efficiency. They also utilize near-infrared light—wavelengths unused by plants—and thrive in diverse environments, including freshwater, seawater, and hot springs. Among these organisms, the marine purple nonsulfur bacterium Rhodovulum sulfidophilum is a model species notable for its strong tolerance to oxygen. However, the molecular mechanism by which its light-harvesting and energy-converting LH1-RC complex maintains highly efficient photosynthesis under oxic conditions remains unclear.