Research Abstract:
Our research program is primarily concerned with elucidating the mechanism of the energy-storing reactions in photosynthetic organisms, as well as understanding the origin and early evolution of photosynthesis.
The processes leading to long-term energy storage in photosynthetic systems take place within the membrane-bound reaction center complex and an associated group of proteins that make up an electron transport chain. One of the central goals of our research is to identify the molecular parameters responsible for the fact that essentially every photon absorbed by the system leads to stable products. To this end, we do a variety of kinetic, thermodynamic and structural measurements on antenna complexes, reaction centers, electron transport proteins and isolated pigments, using a number of techniques, including ultrafast laser flash photolysis and UV-VIS, fluorescence and electron spin resonance spectroscopies, as well as biochemical and molecular biological analysis.
The appearance of photosynthesis and other metabolic processes such as nitrogen fixation had profound effects on the evolution of advanced life on Earth. Our analysis of whole bacterial genomes has revealed that these metabolic processes have complex evolutionary histories, including substantial horizontal gene transfer. We have also used a combination of genomic, molecular evolution techniques and biochemical analysis to identify and characterize previously unknown enzyme complexes with novel activities.
Selected Publications:
Swingley WD, Chen M, Cheung PC, Conrad AL, Dejesa LC, Hao J, Honchak BM, Karbach LE, Kurdoglu A, Lahiri S, Mastrian SD, Miyashita H, Page LE, Ramakrishna P, Satoh S, Sattley WM, Shimada Y, Taylor HL, Tomo T, Tsuchiya T, Wang ZT, Raymond J, Mimuro M, Blankenship RE and Touchman JW. Niche adaptation and genome expansion in the chlorophyll d-producing cyanobacterium Acaryochloris marina. Proc. Nat’l. Acad. Sci. USA 2008 105: 2005-2010.
Swingley WD, Blankenship RE and Raymond J. Using automated Markov clustering to reconstruct the cyanobacterial species tree from conserved protein families. Molec Biol Evol 2008 25: 1-12.
Sattley WM, Madigan MT, Swingley WD, Cheung PC, Clocksin KM, Conrad AL, Dejesa LC, Honchak BM, Jung DO, Karbach LE, Kurdoglu A, Lahiri S, Mastrian SD, Page LE, Taylor HL, Wang ZT, Raymond J, Chen M, Blankenship RE and Touchman JW. The complete genome of Heliobacterium modesticaldum, a phototrophic representative of the Firmicutes containing the simplest known photosynthetic apparatus. J. Bacteriology 2008 190: 4687–4696.
Engel GS, Calhoun TR, Read EL, Ahn TK, Mancal T, Cheng Y-C, Blankenship RE and Fleming GR. Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems. Nature 2007 446: 782-786.
Sadekar S, Raymond J, Blankenship RE. Conservation of Distantly Related Membrane Proteins: Photosynthetic Reaction Centers Share a Common Structural Core. Molec Biol Evol 2006 23: 2001-2007.
Last Updated: 11/13/2008 |