Johann Deisenhofer
Johann Deisenhofer ( born September 30, 1943 in Zusamaltheim, Dillingen an der Donau) is a German biophysicist. It dealt mainly with the structural analysis on the structure and function of protein molecules. For the elucidation of the three-dimensional structure of the photosynthetic reaction center of purple bacteria, he received 1988 he together with Robert Huber and Hartmut Michel received the Nobel Prize for Chemistry.
- 2.1 Early Work
- 2.2 the reaction center of photosynthesis
- 2.3 Further crystallizations and structure elucidation
- 2.4 cholesterol intake
Life and work
Family and school
Johann Deisenhofer is the first child of the farmer Johann Deisenhofer and his wife Thekla (born Magg ), 1948 also his sister Antonia was born. Deisenhofer attended primary school in Zusamaltheim and moved in 1956 to the boys' middle school Holy Cross, Donauwörth. He attended from 1957 to 1959, the Staatliche Realschule Wertingen. His achievements and results justified him in 1959 to visit the Holbein Gymnasium in Augsburg, where in 1963 the Abitur. After 18 months of military service, he took up the study of physics at the Technical University of Munich with a " scholarship for highly gifted " by the Bavarian State Ministry of Education and Culture in 1965. According to the company motivated him above all his interest in modern physics and astronomy to study physics, among other things by reading popular books by Fred Hoyle.
Studies and early research
While studying Deisenhofer noticed that the theoretical physics very much different from his expectations, at the same time he developed increasing interest in solid state physics. In 1971 he completed his diploma thesis in the group of Klaus Dransfeld under the supervision of Karl -Friedrich Renk from, which led to his first scientific publication in 1971, an article in the journal Physical Review Letters about a new technology for the detection of phonons. Dransfeld employed at that time, among other biophysical issues, which Deisenhofer 1971 his doctoral thesis at the Max Planck Institute of Biochemistry (then called "Max - Planck - Institute for Protein and Leather Research" ) in Martinsried near Robert Huber together with Wolfgang Steigemann began. They worked together on the crystallographic refinement of the structure elucidation of the pancreatic trypsin inhibitor of bovine by an optimization of the X-ray structure analysis and the evaluation and the results published in the journal Acta Crystallographica. Deisenhofer finished his dissertation in late 1974 with the work " Crystallographic refinement of the structure of pancreatic trypsin inhibitor at 1.5 Å resolution ".
Following his doctoral thesis to him Huber offered a post- doctoral position at for two years, which he accepted and has been converted to a permanent location in 1976. Deisenhofer worked with Peter M. Colman and Walter Palm of the University of Graz in the human immunoglobulin Kol, a myeloma protein from the group of immunoglobulins of the class G. After the structure determination of this protein, he worked with Huber to 1980 in the work of Peter Colman the human Fc fragment and the complex with an Fc binding part of the protein A of Staphylococcus aureus. Subsequently worked Deisenhofer, among others, structure elucidation of the human C3a, citrate synthase and an alpha- 1-proteinase inhibitor.
Research on photosynthetic reaction center and Nobel Prize
In 1982, he was by Hartmut Michel, who had come together with Dieter Oesterhelt to Martinsried, on the successes in the crystallization of the photosynthetic reaction center of Rhodopseudomonas viridis. Deisenhofer joined the group and began the structural elucidation of the three-dimensional structure of the reaction center. The group was supplemented by Kunio Miki, a post- doctoral students at the University of Osaka, who remained in Martinsried to 1983, and later by Otto Epp. By the end of 1983, the group first gaining popularity, within the next two years was the complete structure are elucidated and another two years later, in 1987, the refinement of the structure to 2.3 Å resolution was complete. Together, the researchers published their findings in December 1985 in the Proceedings of the National Academy of Sciences of the United States of America. Hartmut Michel and Deisenhofer received the 1986 Biological Physics Prize of the American Physical Society and the 1988 Otto Bayer Award. Deisenhofer habilitated in 1987 at the Technical University of Munich in 1988 and received an appointment as Professor of Biochemistry at the University of Texas at Dallas, USA, to establish a working group at the Howard Hughes Medical Institute, UT Southwestern Medical Center.
Also in 1988, he shared with Robert Huber and Hartmut Michel received the Nobel Prize in Chemistry for the X-ray structure analytical elucidation of the three-dimensional structure of the photosynthetic reaction center of the purple bacterium Rhodopseudomonas viridis. As a result, he was honored with other awards, including honorary citizenship in his native Zusamaltheim and his adopted home of Dallas as well as the Order of Merit of the Federal Republic of Germany ( Federal Cross of Merit ) of the Federal Republic of Germany. He was also in 1989 Regen Professor and holder of Virginia and Edward Linthicum Chair in Biomolecular Science at the University of Texas.
Scientific career and life after the Nobel Prize
After the Nobel Prize itself Deisenhofer dealt with further structural elucidation of biomolecules, including some structural problems related to the regulation of the synthesis, the uptake and distribution of cholesterol.
Shortly after his arrival in the U.S. he met Kirsten Fischer Lindahl, Professor of Microbiology and Biochemistry, and also founder of the Howard Hughes Medical Institute, whom he married in 1989. Since 2001, Deisenhofer is officially citizens of the United States, since 2003 he is member of the German Academy of Sciences Leopoldina. Also in 2003, belonged Deisenhofer as one of 22 Nobel Prize winners among the signatories of the 3rd Humanist Manifesto Humanism and Its Aspirations of the American Humanist Association. 2010 signed Deisenhofer together with 255 signatories of the National Academy of Sciences an open letter entitled Climate Change and the Integrity of Science in Science magazine. In the letter, the lack of understanding of the researchers on the handling of politicians with researchers and in particular climate scientists and the Intergovernmental Panel on Climate Change (IPCC ) was expressed in the current debate on global warming.
Research
Early work
The first scientific publication of Johann Deisenhofer is contrary to the results of his thesis on the detection of phonons by a newly developed method. Here 1012 Hz phonons were captured and detected in a ruby crystal variable proportion of Cr3 ions.
In his thesis for the first time Deisenhofer worked on the structural analysis of a protein by refined together with Wolfgang Steigemann the structure elucidation of the pancreatic trypsin inhibitor of bovine by an optimization of the X-ray structure analysis and a resolution of 1.9 and later 1.5 angstroms (Å ) reach could.
Reaction center of photosynthesis
The focus of the research Deisenhofers provide structural analyzes of three-dimensional molecules, especially proteins, dar. During his research at the Max Planck Institute of Biochemistry, he succeeded by a further development and application of X-ray crystallography to elucidate the structure and function of protein molecules. Together with Robert Huber, he worked from 1982 to 1985 on the foundations of photosynthesis and the associated molecules.
The working group, which also includes Hartmut Michel was succeeded for the first time to elucidate the three-dimensional structure of two beteioligter on the photoreaction protein - pigment complexes. These were firstly, a protein that the light captures and forwards and also to a reaction center, which induces the light-driven transport of electrons through a biomembrane. The researchers succeeded for the first time, to get an insight into the function and fine structure of a biological photocell and educate by X-ray structural analysis of the atomic fine structure of the complexes involved. As a model organism, they used it to the purple bacteria Rhodopseudomonas viridis counting. This also managed the first complete X-ray structure analysis of a membrane-bound protein and complex. This is in contrast to protein away from the membrane is not soluble in water and accordingly are difficult to isolate and crystallize.
Further crystallizations and structure elucidation
Both prior to his employment with the elucidation of the three-dimensional structure of the photosynthetic reaction center as well as afterwards Deisenhofer worked on numerous other molecules. It included both Biomolekühle human origin as well as other organisms such as the fruit fly Drosophila melanogaster, or mouse-ear cress (Arabidopsis thaliana ).
Cholesterol intake
One focus of research in recent years turned the inclusion of cholesterol and the structure of associated molecules dar. Here, the working group focused primarily on the Transport of cholesterol necessary low density lipoprotein ( LDL), the membrane- bound proteins NPC1 and NPC1L1 and the free protein NPC2 and PCSK9, proprotein convertase subtilisin the / Kexin Type 9
The Working Group operates, among others, to the elucidation of the structure of proteins NPC1 and NPC1L1, which allow the absorption of cholesterol in the small intestine through the cell membrane and act as a docking point of the drug ezetimibe for inhibiting the absorption of cholesterol in the small intestine. The proteins take over the cholesterol from NPC2 to which it was transferred from the LDL protein. The working group was able to resolve the structure responsible for the binding of N- terminal domain of NPC1 and NPC1L1 and the binding and the complex formed with cholesterol and 25 - hydroxycholesterol. Later they found the selectivity of NPC1L1 for cholesterol dar. based on the structure of the sterol - binding site in the form of a closed pocket