This proposal requests funds to assemble instrumentation for the Center for Photochemistry and Photobiology devoted to x-ray crystallography, magnetic resonance spectroscopy, and dynamic studies of photochemical reaction centers from bacteria, cyanobacteria, algae, and plants. Modern molecular genetic methods will be available for the production of mutant proteins to explore the relationship between structure and function in the centers as well as to study the assembly of the centers in chloroplasts. Major facilities will be created for x-ray diffraction data collection and for magnetic resonance spectroscopy.