The Nobel Prize in Chemistry 1988 was awarded jointly to Johann Deisenhofer, Robert Huber and Hartmut Michel "for the determination of the three-dimensional structure of a photosynthetic reaction centre".
 

A photosynthetic reaction center is a complex set of proteins, pigments and other co-factors where the primary energy conversion reactions of photosynthesis take place. Johann Deisenhofer, Robert Huber and Hartmut Michel are the first to succeed in unravelling the full details of how a membrane-bound protein is built up, revealing the structure of the molecule atom by atom. The protein is taken from a bacterium which, like green plants and algae, uses light energy from the sun to build organic substances. The organic substances serve as nourishment for both plants and animals. Using the oxygen in the air, they consume these nutrients through what is termed cellular respiration. The conversion of energy in photosynthesis and cellular respiration takes place through transport of electrons via a series of proteins, which are bound in special membranes. These membrane-bound proteins are difficult to obtain in a crystalline form that makes it possible to determine their structure, but in 1982 Hartmut Michel succeeded in doing this. Determination of the structure was then carried out in collaboration with Johann Deisenhofer and Robert Huber between 1982 and 1985.