Johann Deisenhofer

Biochemist and biophysicist Johann Deisenhofer (born 1943) devised a way to use X-ray technology to map the chemical reactions central to plant photosynthesis, earning him the Nobel Prize in Chemistry in 1988.

Deisenhofer has spent his career investigating the design and composition of molecular structures. Through his work at the Max-Planck Institute for Biochemistry in his native Germany, Deisenhofer gained experience in the application of X-ray technology as a tool to analyze the structure of crystallized substances. During the 1980s his work aiding a group of German biologists in studying plant photosynthesis--the process whereby light energy from the sun is converted into the chemical energy that maintains life--resulted in the first-ever mapping of the structure of those molecules involved in the chemical reaction integral to the conversion process.

From Farm to Laboratory

Deisenhofer was born on September 30, 1943, in Zusamaltheim, Bavaria (now Germany), a small village located near the city of Munich. His parents, Johann and Thekla (Magg) Deisenhofer, were farmers and they raised Johann with the expectation that, as the only son in their small family, he would take over the responsibility of running the family farm when his father retired. However, the young boy showed more aptitude for academics than he did for farming, and his parents reluctantly came to the conclusion that their son was an intellectual rather than a farmer. In 1956, 13-year-old Johann was sent away to a series of boarding schools, and he graduated from Augsburg's Holbein Gymnasium--a gymnasium is the German equivalent of a North American high school--seven years later in 1963. After passing Germany's mandatory qualifying exam, he earned a state scholarship that allowed him to attend the Technical University in Munich. Prior to enrolling at school, however, Deisenhofer was required to perform a year and a half of compulsory military service, after which he left with the rank of private.

In Munich at last, Deisenhofer decided to focus his studies on physics, the logical outgrowth of the fascination with astronomy he had developed while observing the night sky as a boy and reading popular books by such authors as Fred Hoyle during his years at the gymnasium. The more he explored his academic major, however, the more he found himself drawn specifically to the study of solid-state physics: the study of the composition and structure of condensed matter and solids. During his hours in the laboratory he was inspired by a professor to explore the new and growing area of physics called biophysics: the study of biology using the principles of physical science. In 1971, the same year he graduated with a diploma in physics from Munich's Technical University, Deisenhofer successfully published his first scientific paper in Physical Review Letters. His university thesis meanwhile focused on the detection of terahertz-phonons in a ruby.

Deciding to continue his education in biophysics, in June of 1971 Deisenhofer enrolled as a doctoral candidate at the prestigious Max-Planck Institute for Biochemistry near Munich, where he studied under the direction of Institute director Robert Huber and where he also became well versed in the technique of X-ray crystallography. X-ray crystallography--first used in 1912 by German scientist Max Theodore Felix von Laue to create X-ray diffraction images and employed as well during the mid-twentieth century by University of Cambridge biologists James Watson and Francis Crick as a means of confirming their model of the DNA molecule--is a technique whereby the atomic structure of a purified and crystallized water-soluble substance is studied by exposing the crystal to bursts of radiation of a pre-determined and controlled wavelength. Because the internal atomic structure of water-soluble crystals is ordered into a system of lattices, the wavelength of the X-rays used to scatter the subject crystal's electrons and the measurement of the intensity of the scattered electrons can be combined to allow scientists to map out the crystal's electron and atomic structure. During his research into X-ray crystallography, Deisenhofer focused specifically on a project with fellow student Wolfgang Steigemann wherein the two Ph.D. candidates attempted to determine the atomic structure of Bovine Pancreatic Trypsin Inhibitor. Deisenhofer obtained his Ph.D. from the Max-Planck Institute in 1974, his thesis based on his successful work with Steigemann.

After graduation Deisenhofer stayed at the Max-Planck Institute, content to work alongside Huber as a research scientist. He continued to make advances in the applications for X-ray crystallography and was appointed a staff scientist at the lab in 1976. To supplement his lab work, Deisenhofer also developed a facility with computers and was able to design computer programs that could process the data obtained from the X-ray techniques and produce a map of the atomic structure of the substance in question. As the computers available to the lab became more sophisticated, so did Deisenhofer's programs. Meanwhile, the findings of his work with Steigemann on the Bovine Pancreatic Trypsin Inhibitor while a Ph.D. candidate were published to favorable peer reviews in a 1975 edition of the journal Acta Crystallographica.

Technical Advances Hastened Project

In 1979 Huber and his laboratory associates were joined by German biophysicist Hartmut Michel, who was engaged in the ongoing study of photosynthesis in the hopes of finding a way to obtain a thorough analysis of the molecules involved in the complex chemical-reaction process. Even in the late twentieth century, the detailed process of photosynthesis remained a mystery to scientists, although it was known that an understanding of the structure of the proteins present in cell membranes would be the key to understanding the photosynthetic light-chemical energy transfer. The reason: the light energy sent to the electron in the cell membrane fuels the reaction during which the protein transmits that energy through the cell wall in a chemical form. In September of 1981 Michel successfully hit upon a way to crystallize the photosynthetic reaction center of a purple bacterium called Rhodopseudomonas viridis. He came to Huber for advice, and Huber sent Michel to Deisenhofer, reasoning that with his experience in X-ray crystallography, Deisenhofer would find a way to analyze and map the photosynthetic reaction center.

In less than three years Deisenhofer, with the aid of several assistants, was able to use X-ray crystallography techniques to map the more than 10,000 atoms within the membrane protein complex of Rhodopseudomonas viridis and produce the first three-dimensional structural analysis of a photosynthetic reaction center. Measuring the X-ray diffraction was accomplished quickly with the aid of electronic devices that had replaced the standard X-ray film or more primitive devices used only a few years before. However, the actual computer modeling process went much slower. In fact, two years were needed by Deisenhofer as he repeatedly refined his model of the membrane protein. Using custom-designed software and a high-speed computer to quickly perform the myriad of calculations required to establish the location within the cell of each of the many thousands of atoms contained in that single crystallized protein, the German biophysicist painstakingly supervised the slow formation of the model, a process akin to watching a photograph develop in a darkroom. A computer graphics program he devised took the data relating to X-ray diffraction, combined it with the predetermined wavelength of the relevant radiation, and translated the resulting data into a three-dimensional computer model that has been for scientists a welcome replacement for the classic ball- and-stick models of decades past. Of the future of X-ray crystallography, Deisenhofer predicted to Southwestern Medicine contributor David Doremus: "Progress in this field will closely parallel progress in the development of computers. That's what makes me optimistic--computers have fantastic capabilities now compared to 10 years ago."

Amid the excitement that broke out within the scientific community at the news of Deisenhofer and Michel's accomplishment, a writer in New Scientist heralded the efforts of the scientists at the Max-Planck Institute as "the most important advance in the understanding of photosynthesis" since the mid-1960s, as quoted in Notable Scientists: From 1900 to the Present. Deisenhofer later recalled of his experience in the award-winning project in his autobiography for the Nobel e-Museum: "It was a special privilege to belong to the very small group of people who saw the structural model of this molecule grow on the screen of a computer workstation, and it is hard to describe the excitement I felt during this period of the work."

Received Nobel Prize in Chemistry

In 1988 the Royal Swedish Academy of Sciences announced that the recipients of that year's Nobel Prize in Chemistry were Deisenhofer, Huber, and Michel. In addition to paving the way for the creation of artificial photosynthetic reaction centers, their findings were acknowledged for their potential as tools to gain knowledge about other biologic functions, such as the function of cell hormones, respiration, nutrition, and nerve impulses.

The Nobel Prize changed Deisenhofer's world. Instead of working quietly in his laboratory in Germany, he was now a celebrity of sorts, and he and his award-winning colleagues were asked to present papers and appear at a host of science-related functions. In addition to the Nobel Prize, Deisenhofer was a co- recipient, with Michel, of the American Physical Society's Biological Physics Prize in 1986 and Germany's Otto-Bayer Prize two years later. His other honors include the Knight Commander's Cross of the German Order of Merit and the Bavarian Order of Merit, while honorary degrees have been conferred on him from Drury College of Springfield, Missouri, and Burdwan University of West Bengal, India. A fellow of the American Association for the Advancement of Science since 1992 and named an Argonne fellow in 2001, Deisenhofer also belongs to the American Crystallographic Association, the German and U.S. affiliates of the Biophysical Society, the German Society for Biological Chemistry, the Protein Society, Academia Europaea, Sigma Xi, and has been an honored foreign associate of the U.S. National Academy of Sciences since 1997. He also serves on the University of Chicago board of governors for the Argonne National Laboratory and was inducted into the Texas Science Hall of Fame in 2002. After moving to the United States and establishing a permanent residence in this country, Deisenhofer applied for and was granted dual U.S./German citizenship.

Leaving the Max-Planck Institute and moving to the United States in February of 1988, Deisenhofer accepted the Virginia and Edward Linthicum Distinguished Chair in Biomolecular Science at the University of Texas Southwestern Medical Center (UTSMC) at Dallas. In addition to his role as Regental Professor and professor of biology at UTSMC he also accepted a position as an investigator at the Dallas unit of the Howard Hughes Medical Institute, where he is able to promote the use of X-ray crystallography in the study of water-soluble proteins, membrane proteins, and other macromolecules and develop additional crystallographic software. Early in his tenure at the Texas research center he also met the woman who would become his wife, microbiology professor and fellow Howard Hughes Medical Institute investigator Kirsten Fischer Lindahl. Deisenhofer and Lindahl were married in 1989 and continue to make their home near Dallas, Texas.

Although Deisenhofer has a reputation for being shy and totally involved in his work, he also finds time to enjoy music and chess, swimming and skiing, and is an amateur history buff. As an outgrowth of his lab work, in 1993 he joined fellow scientist James R. Norris of the Argonne National Laboratory in writing the two-volume book The Photosynthetic Reaction Center, based on research emanating from his Nobel Prize-winning investigation into photosynthesis. Other research by Deisenhofer has been published in Science, Journal of Molecular Biology, Journal of Biological Chemistry, EMBO Journal, Nature, and other scientific journals. Among his continuing goals as a scientist is the ability to discover the rules defining the three-dimensional structure of proteins. By learning this, the biophysicist reasons, scientists will be a good deal closer to understanding the basic structural component of all life on Earth.

Further Reading

• Notable Scientists: From 1900 to the Present, Gale Group, 2001.
• Physics Today, February 1989.
• Science, November 4, 1988.
• Scientific American, December 1988.
• Southwestern Medicine (University of Texas Southwestern Medical Center), 1991.
• Time, October 31, 1988.
• "Dr. Johann Deisenhofer," Texas Hall of Fame for Science, Mathematics and Technology, http://www.texassciencesummit.org/halloffame/scannedinfo/newdeise nhoferbio1.htm (December 28, 2002).
• "Johann Deisenhofer-Autobiography," Nobel e-Museum, http://www.nobel.se/chemistry/laureates/1988/deisenhofer-autobio.html (February 11, 2002).
• "Johann Deisenhofer, Ph.D.," University of Texas Southwestern, http://www.swnt240.swmed.edu/gradschool/webrib/deisenhofer.htm (September 11, 2002).