Michel, Hartmut (1948-), a German biochemist, was the first to successfully crystallize a molecule important in photosynthesis. He shared the 1988 Nobel Prize in chemistry with his collagues Robert Huber and Johann Deisenhofer for determining the three-dimensional structure of a photosynthetic reaction center. Their discovery was an important advance in the study of giant molecules involved in living processes. In 1985, they identified and placed more than 10,000 atoms in the molecule.
Michel was born in Ludwigsburg, Württemberg, in southwestern Germany. He became interested in physics and molecular biology while in high school. In 1969, after completing military service, he enrolled at the University of Tübingen, near Stuttgart, Germany. There he studied biochemistry, including the activity of enzymes (proteins that promote biochemical reactions) in certain bacteria. During that time, he worked at the Max Planck Institute for Biochemistry at Martinsried, near Munich, Germany. He earned a doctorate from the University of Würzburg in 1977.
That year, Michel worked on a protein called bacteriorhodopsin, which is found in the membranes (outer coverings) of cells, and is involved in photosynthesis. He observed that bacteriorhodopsin became semicrystallized when frozen. Scientists had thought it impossible to crystallize membrane proteins because they would not combine with water to form a crystal structure. The proteins could not be studied with X-ray crystallography, which involves scattering X rays from the rows of regularly spaced atoms in a crystal.
Using detergents instead of water, Michel succeeded in crystallizing bacteriorhodopsin, but the crystals were too small and too disordered for a structural analysis. In 1981, he successfully crystallized a large molecule from the bacterium Rhodopseudomonas viridis and obtained a good X-ray image of it. The molecule consisted of 4 proteins and 14 other components and served as the bacterium's photosynthetic reaction center.
In 1987, Michel became a director and department head of the Max Planck Institute in Frank-furt-am-Main.