In recent years, my laboratory has focused on a biochemical process of great environmental interest, the means by which bacteria oxidize manganese, producing the MnO2 deposits found in soils and sediments. Through systematic studies of the first isolated manganese oxidase enzyme, Mnx, we have been able to unravel the novel chemistry driving this process. We have shown that the enzyme overcomes the Mn(III) barrier through formation of hydroxide-bridged binuclear complexes in each of the three Mn oxidation states. Work now focusses on the structure of the enzyme and of the chemical intermediates on the pathway, using cryo-electron microscopy and x-ray absorption spectroscopy. The results are expected to inform long-standing questions about manganese biomineralization in the environment, as well as the design of Mn catalysts.
Soldatova, A. V.; Tao, L.; Romano, C. A.; Stich, T. A.; Casey, W. H.; Britt, R. D.; Tebo, B. M.; Spiro, T. G., Mn(II) oxidation by the multicopper oxidase complex Mnx: A binuclear activation mechanism. Journal of the American Chemical Society 2017, 139, 11369−11380. http://dx.doi.org/10.1021/jacs.7b02771
Soldatova, A. V.; Romano, C. A.; Tao, L.; Stich, T. A.; Casey, W. H.; Britt, R. D.; Tebo, B. M.; Spiro, T. G., Mn(II) oxidation by the multicopper oxidase Mnx: A coordinated two-stage Mn(II)/(III) and Mn(III)/(IV) mechanism. Journal of the American Chemical Society 2017, 139, 11381−11391. http://dx.doi.org/10.1021/jacs.7b02772
Soldatova, A. V.; Balakrishnan, G.; Oyerinde, O. F.; Romano, C. A.; Tebo, B. M. Spiro, T. G., Biogenic and synthetic MnO2 nanoparticles: size and growth probed with absorption and Raman spectroscopies and dynamic light scattering. Environmental Science & Technology 2019, 53 (8), 4185-4197. https://doi.org/10.1021/acs.est.8b05806