Assistant Professor of Chemistry
Ph.D. ETH Zurich, 2003
(Biophysical, Materials, Physical Chemistry)
Our lab revolves around unpaired electrons. We work on elucidating structure and function of spin centers in their diverse roles in both natural and human-designed molecular systems, using Electron Paramagnetic Resonance (EPR) spectroscopy as a central tool.
Many of the most difficult and complex chemical transformations in Nature make use of single-electron chemistry. Enzymes use transition metal ions, metal ion clusters, and very reactive organic radicals in their catalytic centers to perform difficult redox chemistry. Many of these reactions are essential to life, and some of them are pathologically relevant. We study the structural and dynamic details of these reactions to understand how Nature generates, harnesses and controls reactive paramagnetic intermediates.
Structure of proteins and protein complexes
We are using DEER, an advanced EPR technique, to develop coarse-grain structural models of proteins and protein complexes. DEER can measure absolute distances of up to 8 nm with a precision of 0.1 nm between spin labels attached to cysteine residues in site-directed mutants.
Materials for energy
Single unpaired electrons are at the core of natural processes that harvest light and convert it to chemical energy. Similarly, artificial energy conversion systems use electrons to capture light, transport the energy and transform it into a usable form. At an atomic level, many processes are still poorly understood. We are elucidating the inner workings of various energy conversion systems, using high-resolution and time-resolved EPR techniques. The structural and dynamic insight will help improve the designs and efficiencies of materials and devices.
We use EPR spectroscopy in all its basic and advanced variants as our core technology. We are developing improved theory, software, and hardware to gain faster, more detailed and more robust results through increased sensitivity and resolution of measurements and increased reliability and ease of data interpretation.
M. C. Puljung, H. A. DeBerg, W. N. Zagotta, S. Stoll "Double electron-electron resonance reveals cAMP-induced conformational change in HCN channels" Proc. Natl. Acad. Sci. USA, 111, 9816-9821 (2014)
S. Stoll, Y.-T. Lee, M. Zhang, R. F. Wilson, R. D. Britt, D. B. Goodin, "Double electron-electron resonance shows cytochrome P450cam undergoes a conformational change in solution upoin binding substrate" Proc. Natl. Acad. Sci 109, 12888-12893 (2012)
S. Stoll, H. S. Shafaat, J. Krzystek, A. Ozarowski, M. J. Tauber, J. E. Kim, R. D. Britt "Hydrogen bonding of tryptophan radicals revealed by EPR at 700 GHz" J. Am. Chem. Soc. 133, 18098-18101 (2011)
A. M. Taylor, S. Stoll, R. D. Britt, J. T. Jarrett "Reduction of the [2Fe-2S] Cluster Accompanies Formation of the Intermediate 9-Mercaptodethiobiotin in Escherichia coli Biotin Synthase" Biochemistry 50, 7953-7963 (2011)
S. Stoll, A. Ozarowski, R.D. Britt, A. Angerhofer "Atomic Hydrogen as High-Precision Field Standard for High-Field EPR" J. Magn. Reson. 207, 158-163 (2010)
M. M. Dicus, A. Conlan, R. Nechushtai, P. A. Jennings, M. L. Paddock, R. D. Britt, S. Stoll "The Binding of Histidine in the (Cys)3(His)1-coordinated [2Fe-2S] Cluster in Human mitoNEET" J. Am. Chem. Soc. 132, 2037-2049 (2010)
S. Stoll, R. D. Britt
"General and efficient simulation of pulse EPR spectra" Phys. Chem. Chem. Phys. 11, 6614-6625 (2009)
S. Stoll, A. Gunn, M. Brynda, W. Sughrue, A. Kohler, A. Ozarowski, A. J. Fisher, J. C. Lagarias, R. D. Britt
"Structure of the biliverdin radical intermediate in phycocyanobilin:ferredoxin oxidoreductase identified by high-field EPR and DFT"
J. Am. Chem. Soc. 131, 1986-1995 (2009)