Together with Michel and Huber, Deisenhofer determined the three-dimensional structure of a protein complex found in certain photosynthetic bacteria. This membrane protein complex, called a photosynthetic reaction center, was known to play a crucial role in initiating a simple type of photosynthesis. Between 1982 and 1985, the three Scientists used X-ray crystallography to determine the exact arrangement of the more than 10,000 atoms that make up the protein complex. Their research increased the general understanding of the mechanisms of photosynthesis and revealed similarities between the photosynthetic processes of plants and bacteria.