Research on photosynthetic reaction centers from 1932 to 1987.

The history of research on photosynthetic reaction centers is outlined, starting with the implication of their existence through the discovery of the photosynthetic unit, as reported by R. Emerson and W. Arnold in 1932, and culminating in the crystallization and X-ray analysis of the anoxygenic bacterial reaction centers, reported by J. Deisenhofer, H. Michel, and coworkers, over the period 1982-1987. Reaction centers of purple photosynthetic bacteria have received the most attention because they have been well purified and characterized. Structures of cyanobacterial reaction centers of Photosystems I and II are now available from the laboratories of H. Witt and W. Saenger.