Associate Professor of Chemistry
Adjunct Associate Professor of Physiology & Biophysics
Ph.D. ETH Zürich, 2003
(Biophysics, Spectroscopy, and Physical Chemistry)
The Stoll lab focuses on determining the structure and function of proteins and enzymes in their diverse roles in both natural and human-designed molecular systems, using advanced electron paramagnetic resonance (EPR) spectroscopy as a central tool.
Quantifying protein conformational landscapes
Proteins need to be flexible in order to perform their function, such as catalysis, transport, or signaling. We study the conformational flexibility of proteins and how they move, with the goal of increasing the knowledge base about these fundamental processes. We use double electron-electron resonance (DEER) spectroscopy, an advanced EPR technique, to quantify the structural, energetic and dynamic aspects of conformational flexibility and change. DEER measures absolute distances and distance distributions between labels attached to specific sites in proteins, with a range of 15-80 Å and a precision of < 1 Å.
Radical and metalloenzymes
Many difficult and complex chemical transformations are catalyzed by enzymes with transition metal ions, metal ion clusters, and very reactive organic radicals in their catalytic centers. 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 in these enzymes.
Our core technology is EPR spectroscopy in all its basic and advanced variants. EPR reveals the structure and dynamics of the nanoenvironment around unpaired electrons. We develop 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 reproducibility of data analysis and interpretation. Our Matlab-based software EasySpin for the simulation and analysis of EPR spectra is widely used.
The Stoll lab revolves around unpaired electrons. Our interests thus extend to other topics involving electron spins, such as energy conversion materials, molecular magnetism, and quantum computing.
Collauto, A.; DeBerg, H. A.; Kaufmann, R.; Zagotta, W. N.; Stoll, S.; Goldfarb, D. Rates and equilibrium constants of the ligand-induced conformational transition of an HCN ion channel protein domain determined by DEER spectroscopy. Phys. Chem. Chem. Phys. 2017, 19, 15324–15334.
Tait, C. E.; Stoll, S. ENDOR with band-selective shaped inversion pulses. J. Magn. Reson. 2017, 277, 36–44.
Hayes, E. C.; Jian, Y.; Li, L.; Stoll, S. EPR study of UV-irradiated thymidine microcrystals supports radical mechanism in spore photoproduct formation. J. Phys. Chem. B 2016, 120, 10923–10931.
Edwards, T. H.; Stoll, S. A Bayesian approach to quantifying uncertainty from experimental noise in DEER spectroscopy. J. Magn. Reson. 2016, 270, 87–97.
Tait, C. E.; Stoll, S. Coherent pump pulses in Double Electron Electron Resonance spectroscopy. Phys. Chem. Chem. Phys. 2016, 18, 18470–18485.
Hayes, E. C.; Porter, T. R.; Barrows, C. J.; Kaminsky, W.; Mayer, J. M.; Stoll, S. Electronic structure of a CuII-alkoxide complex modeling intermediates in copper-catalyzed alcohol oxidations. J. Am. Chem. Soc. 2016, 138, 4132–4145.
DeBerg, H. A.; Brzovic, P. S.; Flynn, G. E.; Zagotta, W. N.; Stoll, S. Structure and energetics of allosteric regulation of HCN2 ion channels by cyclic nucleotides. J. Biol. Chem. 2016, 291, 371–381.
DeBerg, H. A.; Bankston, J. R.; Rosenbaum, J. C.; Brzovic, P. S.; Zagotta, W. N.; Stoll, S. Structural mechanism for the regulation of HCN ion channels by the accessory protein TRIP8b. Structure 2015, 23, 734–744.
Nehrkorn, J.; Schnegg, A.; Holldack, K.; Stoll, S. General magnetic transition dipole moments for Electron Paramagnetic Resonance. Phys. Rev. Lett. 2015, 114, 010801.
Puljung, M. C.; DeBerg, H. A.; Zagotta, W. N.; Stoll, S. Double electron-electron resonance reveals cAMP-induced conformational change in HCN channels. Proc. Natl. Acad. Sci. USA 2014, 111, 9816–9821.
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. 2012, 109, 12888-12893.
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. 2011, 133, 18098-18101.
S. Stoll, R. D. Britt General and efficient simulation of pulse EPR spectra
Phys. Chem. Chem. Phys. 2009, 11, 6614-6625.