Hartmut Michel

MICHEL. HARTMUT (1948-1. Awarded Nohel prize for chemistry in 1988. along with Johann Deisenhofer and Michel Huber, for work that revealed the three-dimensional structure of closely-linked proteins that are essential to photosynthesis. Doctorate awarded in 1977 h.v the University of Wurtzbuig. Germany. 

Michel, Hartmut (b. 1948) German biochemist who, working with Robert Huber and Johann Deisenhofer, established the structure of an area of a bacterium in which photosynthesis takes place. He and his colleagues were awarded the 1988 Nobel Prize in chemistry for this work. 

The crystallographic world was stunned when at a meeting in Erice, Sicily, in 1982, Hartmut Michel of the Max-Planck Institute in Martinsried, Germany, displayed the x-ray diagram shown in Figure 12.12. Not only was this the first x-ray picture to high resolution of a membrane protein, but the crystal was... 

What molecular architecture couples the absorption of light energy to rapid electron-transfer events, in turn coupling these e transfers to proton translocations so that ATP synthesis is possible Part of the answer to this question lies in the membrane-associated nature of the photosystems. Membrane proteins have been difficult to study due to their insolubility in the usual aqueous solvents employed in protein biochemistry. A major breakthrough occurred in 1984 when Johann Deisenhofer, Hartmut Michel, and Robert Huber reported the first X-ray crystallographic analysis of a membrane protein. To the great benefit of photosynthesis research, this protein was the reaction center from the photosynthetic purple bacterium Rhodopseudomonas viridis. This research earned these three scientists the 1984 Nobel Prize in chemistry. 

Johan Diesenhofer, Robert Huber, and Hartmut Michel Chemistry Three-dimensional structure of a photosynthetic reaction center... 

The crystal structure of reaction centers from R. viridis was determined by Hartmut Michel, Johann Deisenhofer, Robert Huber, and their colleagues in 1984. This was the first high-resolution crystal structure to be obtained for an integral membrane protein. Reaction centers from another species, Rhodobacter sphaeroides, subsequently proved to have a similar structure. In both species, the bacteriochlorophyll and bacteriopheophytin, the iron atom and the quinones are all on two of the polypeptides, which are folded into a series of a helices that pass back and forth across the cell membrane (fig. 15.1 la). The third polypeptide resides largely on the cytoplasmic side of the membrane, but it also has one transmembrane a helix. The cytochrome subunit of the reaction center in R. viridis sits on the external (periplasmic) surface of the membrane. 

The Nobel Prize in chemistry was awarded to Johan Deisenhofer, Robert Huber, and Hartmut Michel in 1988 for unraveling the structure of the reaction center from the purple photosynthetic bacterium Rhodopseudomonas viridis using X-ray crystallography. 

Relatively few membrane transport proteins have been structurally characterized. Some of the best understood examples to date are the lactose permease and glycerol-3-phosphate transporter and the Ca + P-type ATPase (which is a primary ion pump). Other structurally well-characterized transport proteins include the bacterial porins and siderophore receptor proteins. In addition structures have been determined for several ion channels and additional bacterial transporters that are either directly relevant to or models for proteins important in drug transport. The following web sites maintained by Hartmut Michel and Stephen White respectively, contain exceptionally useful listings of these and other solved membrane protein structures and are frequently updated ... 

Hartmut Michel is a Member of Leopoldina (the oldest German science academy, in Halle), the Academy of Sciences of Gottingen, and the Academia Europaea, among others. He is a Foreign Member of the National Academy of Sciences of the U.S.A., the Royal Dutch Academy of Sciences, and the Chinese Academy of Sciences. He has received... 

Johann Deisenhofer and Hartmut Michel at the reception of the Nobel Foundation during the centennial Nobel celebrations in Stockholm, December 2001 (photograph by I. Hargittai). 

Dr. Deisenhofer is a Foreign Associate of the National Academy of Sciences (Washington, D.C., 1997) and a Member of the Academia Europaea (1989). He shared the Biological Physics Prize of the American Physical Society (1986) and the Otto-Bayer-Preis (Germany, 1988) with Hartmut Michel. He received The Knight Commander s Cross of the... 

Hartmut Michel was the biochemist who had been studying membrane proteins for quite a while before starting the work on photosynthetic reaction centers. He was not a crystallographer but he had the firm determination to crystallize membrane proteins. He started with the well-known bacterio-rhodopsin, which is a guinea pig for membrane protein work. Hartmut s boss at that time, Dieter Oesterhelt was one of the pioneers to recognize what bacteriorhodopsin is actually doing. Oesterhelt and Walter Stoeckenius, a researcher with whom Oesterhelt worked at that time in California, had discovered bacteriorhodopsin and then Oesterhelt proposed its function. 

In my view Oesterhelt should ve been included if the rules had permitted this. He supported the project at a time when it was not clear whether it would work or not. He was the director of an Abteilung in the Max Planck Institute for Biochemistry and Robert Huber was also director of an Abteilung. Hartmut Michel worked in Oesterhelt s Abteilung and I worked in Robert Huber s Abteilung. It must have been a difficult choice for the Nobel Committee because there were many different ways in which that prize could ve been given, to Oesterhelt and Huber, to Michel and myself, or some other combination. 

This is a complicated question. It can only be understood in the context of that time. I realized that with the work on the reaction center I had a very good chance to get an independent position somewhere. The Max Planck Society offered a job as a director to Hartmut Michel but, at that time, not to me. I had contacts with universities in Germany and with the European Molecular Biology Laboratory in Heidelberg. At that time I also made many trips to the United States, by invitation, to talk about this story. In the summer of 1986, two years after we had completed the structure I received a letter from this institution, the University of Texas Southwestern Medical Center. It was motivated, as I now know, by the... 

Hartmut Michel determined. It was clearly a breakthrough in understanding the electron transfer in the process of photosynthesis. Our earlier works were the basis that all the tools and instruments and methods were available in our laboratory to enable us to take up such a large project, which at that time was the most complex system to date in crystallography. 

It was when Hartmut Michel joined in. He was an associate of Dieter Oesterhelt here in the same Institute. He had already worked for some time on the preparation of membrane proteins. One day he came and he had some crystals of the protein from the purple bacterium Rhodopseudomonas viridis., and we put these crystals into our X-ray camera. These first crystals were not too good but they were promising. He then improved his procedure... 

Not directly but he was important as the Doktor-Vater of Hartmut Michel and certainly brought Michel towards biochemistry and the crystallization attempts of membrane proteins. 

I was involved in the project while Oesterhelt, with some purpose, kept out. He let Hartmut Michel do this entirely independently. 

Hartmut Michel was Dieter Oesterhelfs associate and Johann Deisenhofer was yours. Oesterhelt was also a director at the Max Planck Institute so you were of equal ranking. Then came the Nobel Prize, which included Deisenhofer, Huber, and Michel. Oesterhelt was not a co-author of the papers reportin 0 the structure determination of the photosynthetic reaction center, and more than three persons could not have shared the Nobel Prize in the first place. My question is, how much change did the Nobel Prize introduce into your careers Was there a watershed effect ... 

Johan Diesenhofer, Robert Huber, and Hartmut Michel... 

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