First Structures of Transmembrane Proteins and Protein-Lipid InteractionsBeginning around 1984, while working as a postdoc with George Feher at UCSD, Jim Allen was able to grow good single crystals of the bacterial photosynthetic reaction center (RC) from Rb. sphaeroides. A collaboration was initiated with Doug Rees' lab at UCLA, where we participated in the crystallographic work. No structures had been determined yet of transmembrane proteins, but in Germany, Deisenhofer, Michel, and Huber were already further along with their work on the homologous complex from Rps. viridis. Their tracing of the RC structure was reported in 1984, and refined in 1985. Structures of the sphaeroides RC based on Jim Allen's crystals were reported beginning in 1987. Although the sphaeroides RC was the second transmembrane protein structure reported, it provided some of the first analyses of protein-lipid interactions and structural properties of a protein in its membrane environment (Yeates, et al. 1987. Structure of the Reaction Center from Rhodobacter sphaeroides R-26: Membrane -Protein Interactions, PNAS 84, 6438-42). Programs written by Doug were used to analyze what regions of the transmembrane protein complex were likely to be in contact with the lipid bilayer. The amino acid composition of the transmembrane surface of the reaction center was analyzed. It was also noted that the amino acid sequence variability between homologs was higher in the lipid-facing residues compared to the residues in the protein interior.In the Rees lab, subsequent work on the reaction center was carried out by Hiromi Komiya, Art Chirino, Michael Stowell, Herb Axelrod, Barbara Hsu, and others. Diesenhofer, Michel, and Huber earned the Nobel Prize in Chemistry in 1998 for their work on the reaction center structure. |
[Figures from Yeates, et al. 1987, PNAS 84, 6438-6442.] The structure of the Rb. sphaeroides reaction center and its optimized position in a lipid bilayer. 
Illustration of a simplified energetic calculation
to determine as precisely as possible how the
reaction center sits in the membrane.
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