Universal free-energy landscape produces efficient and reversible electron bifurcation.


Yuly, JL; Zhang, P; Lubner, CE; Peters, JW; Beratan, DN


For decades, it was unknown how electron-bifurcating systems in nature prevented energy-wasting short-circuiting reactions that have large driving forces, so synthetic electron-bifurcating molecular machines could not be designed and built. The underpinning free-energy landscapes for electron bifurcation were also enigmatic. We predict that a simple and universal free-energy landscape enables electron bifurcation, and we show that it enables high-efficiency bifurcation with limited short-circuiting (the EB scheme). The landscape relies on steep free-energy slopes in the two redox branches to insulate against short-circuiting using an electron occupancy blockade effect, without relying on nuanced changes in the microscopic rate constants for the short-circuiting reactions. The EB scheme thus unifies a body of observations on biological catalysis and energy conversion, and the scheme provides a blueprint to guide future campaigns to establish synthetic electron bifurcation machines.


Yuly, J. L., P. Zhang, C. E. Lubner, J. W. Peters, and D. N. Beratan. “Universal free-energy landscape produces efficient and reversible electron bifurcation.” Proceedings of the National Academy of Sciences of the United States of America 117, no. 35 (September 2020): 21045–51. https://doi.org/10.1073/pnas.2010815117.

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