I am a physical chemist using laser spectroscopy, mass spectrometry, and chemical simulations to build new pictures of how proteins and catalysts operate on the molecular scale. My recent research projects focus on:
Ion binding processes in biological signaling
Developing new experimental methods to probe the structure of reative chemical intermediates (such as those formed by the Ni-cyclam CO2 reduction catalyst)
The intrinsic spectral responses of the nitrile-containing vibrational reporters used to probe protein structure and dynamics.
I think making science accessible and welcoming to people from all backgrounds is key to an effective, innovative, and resilient research enterprise. But, more importantly, it's just the right thing to do. So, I am always working on making my teaching as inclusive as it can be, and on developing worthwhile outreach activities to inspire and encourage scientists-to-be.
Signaling processes mediated by sensor proteins like those in the EF-hand family are essential to life in all eukaryotic cells. One particularly well-studied example, calmodulin, serves as a popular model for ion binding and activation in proteins. It transduces complex calcium signals and acts on hundreds of effector proteins, but the sensitivity and complexity of this process make it difficult to characterize. Much work uses lanthanides as luminescent calcium substitutes to study ion binding and activation in calmodulin and other proteins. This project exploits the time resolution and structural sensitivity of two-dimensional infarared spectroscopy to examine how calmodulin responds to binding with different divalent and trivalent ions and explores the ways in which substituting lanthanides for calcium indeed perturb calmodulin's binding site structure.
Experimental methods for probing intermediate structure in catalysis
A major challenge in chemistry is to study the structure and reactivity of intermediates formed in catalysis. These species often have short lifetimes and are too unstable to analyze using traditional techniques, such as X-ray diffraction or NMR spectroscopy. This project fuses inert atmosphere chemical reduction techniques, electrospray ionization (ESI) mass spectrometry, and cryogenic ion infrared spectroscopy into an experimental protocol capable of probing activated catalytic complexes.
Intrinsic responses of nitrile vibrational probes
Spectroscopic reporters incorporating nitrile groups have emerged as a powerful tool for probing the structure and dynamics of proteins with the tools of infrared spectroscopy. However, solution-phase characterization of the probe response to its environment, encoded as the local electric field, is complicated by the response of the solvent. This project exploits cryogenic infrared predissocation spectroscopy to capture the spectral response of nitrile vibrational probes free from solvent effects.
Chemical reduction of NiII cyclam and characterization of isolated NiI cyclam with cryogenic vibrational spectroscopy and inert-gas-mediated high-resolution mass spectrometry SC Edington (gs) , EH Perez (gs) , FS Menges (rg) , N Hazari (www) , MA Johnson (gs, W) J. Phys. Chem. A , 125, 31, pp 6715-6721 DOI: 10.1021/acs.jpca.1c05016
Infrared spectroscopy probes ion binding geometries SC Edington (gs) , S Liu (li) , CR Baiz (gs) Methods in Enzymology , 651, pp 157-191 DOI: 10.1016/bs.mie.2020.12.028
Mapping the temperature-dependent and network site-specific onset of spectral diffusion at the surface of a water cluster cage N Yang (gs) , SC Edington (gs) , TH Choi (gs) , EV Henderson, JP Heindel (gs) , SS Xantheas (gs, W) , KD Jordan (gs, W) , MA Johnson (gs, W) Proc. Natl. Acad. Sci. USA , 117, 42, pp 20647-20652 DOI: 10.1073/pnas.2017150117
Integration of high-resolution mass spectrometry with cryogenic ion vibrational spectroscopy FS Menges (rg) , EH Perez (gs) , SC Edington (gs) , CH Duong (gs) , N Yang (gs) , MA Johnson (gs, W) J. Amer. Soc. Mass. Spectrom. , 30, pp 1551-1557 DOI: 10.1007/s13361-019-02238-y
Non-additive effects of binding site mutations in calmodulin SC Edington (gs) , DB Halling (www) , SM Bennett (li) , TR Middendorf (www) , RW Aldrich (gs, W) , CR Baiz (gs) Biochemistry , 58, 24, pp 2730-2739 DOI: 10.1021/acs.biochem.9b00096
Vibrational relaxation in EDTA is ion-dependent SC Edington (gs) , CR Baiz (gs) J. Phys. Chem. A , 122, 32, pp 6585-6592 DOI: 10.1021/acs.jpca.8b06075
Coordination to lanthanide ions distorts binding site conformation in calmodulin SC Edington (gs) , A Gonzalez (www) , DB Halling (www) , SM Bennett (li) , TR Middendorf (www) , RW Aldrich (gs, W) , CR Baiz (gs) Proc. Natl. Acad. Sci. USA , 115, 14, pp 3126-3134 DOI: 10.1073/pnas.1722042115
An empirical IR frequency map for ester C═O stretching vibrations SC Edington (gs) , JC Flanagan (gs) , CR Baiz (gs) J. Phys. Chem. A , 120, 22, pp 3888-3896 DOI: 10.1021/acs.jpca.6b02887
A study of stabilization of P3HT/PCBM organic solar cells by photochemical active TiOx layer J Li (li) , S Kim (rg) , S Edington (gs) , J Nedy (gs) , S Cho (gs) , K Lee (rg, www, W) , AJ Heeger (gs, W) , MC Gupta (gs, www) , JT Yates Jr (W) Solar Energy Materials and Solar Cells , 95, 4, pp 1123-1130 DOI: 10.1016/j.solmat.2010.12.030
Enhancement of adsorption inside single-walled carbon nanotubes: Li doping effect on n-heptane van der Waals bonding M Büttner (gs) , L Xiao (rg) , L Mandeltort (gs) , S Edington (gs) , JK Johnson (gs) , JT Yates Jr (W) J. Phys. Chem. C , 113, 12, pp 4829-4838 DOI: 10.1021/jp810139q
Ph.D., Physical Chemistry, Princeton University (2015)
M.A., Physical Chemistry, Princeton University (2011)