How Photosynthetic Reaction Centers Work, Where They Came From, and How We Might Make Our Own
Kevin Redding, Arizona State University
Photosynthetic reaction centers (RCs) are one of life’s most ancient and most useful devices, allowing the biosphere to exploit the abundant solar energy continuously striking our planet and to diversify into a huge number of species with distinct bioenergetic strategies. All known RCs have symmetric structures, using two similar or identical integral membrane polypeptides to form a cage around the cofactors (e.g. chlorophyll, quinones, iron-sulfur clusters) through which electrons are transferred, driven by absorption of light. Our research group uses a combination of molecular genetics and advanced spectroscopic techniques to map out the electron transfer reactions (some of which occur in a few picoseconds) and assess the role of various parts of the protein in directing and influencing these reactions. In this talk, I will present some specific examples of this, and then try to put them into context by presenting a model of how the different RCs may have evolved (>2 billion years ago) from a common ancestral protein. Finally, I will show some examples of how our Center for Bio-Inspired Solar Fuel Production has begun to work on artificial catalysts for light-driven water-splitting (to oxygen and hydrogen) using principles derived from natural photosynthesis.
Background Review Article:
R. E. Blankenship, et al., Comparing Photosynthetic and Photovoltaic Efficiencies and Recognizing the Potential for Improvement. Science 332, 805 (2011).