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John GolbeckProfessor of Biochemistry and Biophysics 310 South Frear Laboratory, University Park, PA 16802 B.S. in Chemistry from Valparaiso University Golbeck Lab Web Site |
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Green sulfur bacteria (Chlorobiaceae) represent a group of strictly anaerobic and obligatorily phototrophic prokaryotes that use sulfide as the electron donor in photosynthesis. These organisms have a Type I photosynthetic reaction center that resembles Photosystem I, and a unique, highly efficient, light harvesting structure termed a chlorosome that contains up to 200,000 chlorophyll antenna molecules (Figure 2.3). In some instances the molecular architecture, the identity of the cofactors, and the kinetics of the acceptors in green bacterial RCs are similar to PS I but in other instances they are unique. My students and I are involved in study of the initial charge separation, the identity of an electron acceptor equivalent to the A1 phylloquinone in PS I, and the function of the chlorosome envelope proteins CsmI, CsmJ and CsmX that contain [2Fe-2S] clusters. Heliobacteria also contain Type I reaction centers and a homodimeric core, but they do not contain chlorosomes, the FMO protein or any known extended antenna system. |
 Figure 2.3. Cartoon depicting the chlorosome and photosynthetic reaction center in Chlorobium tepidum. Figure courtesy of N. Frigaard. |
Given the absence of these structures, the heliobacterial RC should be ideal for study of a prototypical homodimeric reaction centers. We are trying to fill in the gaps in our knowledge with regard to the polypeptide composition of the heliobacterial reaction center, and with regard to the nature of the cofactors that comprise the electron donor and acceptors. |
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If you would like to learn more about individual projects, please follow these links: |
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The Green Sulfur Bacterial Reaction Center The Heliobacterial Reaction Center |
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