people
|Faculty
|Sunil Saxena
 |
Sunil Saxena Department of Chemistry |
The intellectual thrust of the Saxena Group is focused on developing Fourier Transform electron spin resonance and its application to otherwise inaccessible problems in biophysics. The coupling of electron spin angular momentum to its environment – as revealed by the ESR spectrum – provides rich information about the electronic, structural and dynamical properties of the molecule. We are interested in measuring the precise distance between two units in a protein, in order to determine their folding patterns and conformational dynamics. To this end we develop FT-ESR Spectroscopic Rulers – multiple quantum and double resonance ESR experiments – that directly measure distances in the 1 – 7 nm lengthscale. Much of this work is based on the use of first-principles theory to develop new experimental protocols and to analyze experimental results. Our group continues to develop applications of these spectroscopic rulers that range from capturing the essence of structural changes – such as misfolding - in proteins, to measuring the atomic-level details of ion-permeation in a ligand gated ion-channel. We invite you to contact us to explore the diversity of research projects currently underway in our group.
Projects include:
· New FT-ESR methods for measuring distances in systems containing paramagnetic metals, for application to metalloproteins.
· Protein unfolding using room temperature ESR distance measurements.
· spin directed spin labeling of the Glycine receptor
· Measurement of structure and functional dynamics of the
Glycine Receptor.
· Application of the spectroscopic ruler to measure global structures of nanostructured materials.
Awards
NSF CAREER AWARD, 2004-2009
Selected Publications
"Flexibility and lengths of bis-peptide nanostructures by ESR," S. Pornsuwan, G. Bird, C.E. Schafmeister, S. Saxena, J. Am. Chem. Soc., 2006, 128, 3876 (http://dx.doi.org/10.1021/ja058143e)
"Unfolding of alanine-based peptides using electron spin resonance distance measurements," S. Jun, J. Becker, M. Yonkunas, R. Coalson, S. Saxena, , 2006, submitted
"Multiple distance measurements in a ligand gated ion channel using electron spin resonance," K. Stone, Z. Yang. M. Bonora, M. Cascio, S. Saxena, , 2006, submitted
"Double Quantum Coherence Electron Spin Resonance on coupled Cu(II)-Cu(II) electron spins," J. Becker and S. Saxena, Chem. Phys. Lett., 2005, 414, 248
"Nitroxide spin-relaxation over the entire motional range," M. Bonora, S. Pornsuwan and S. Saxena, J. Phys. Chem. B, 2004, 108, 4196
"Suppression of electron spin echo envelope modulation peaks in double quantum coherence electron spin resonance," M. Bonora, J. Becker, and S. Saxena, J. Magn. Reson., 2004, 170, 278
"Amplification of xenon NMR and MRI by remote detection," A. J. Moule, M. M. Spence, S.-I. Han, J. A. Seeley, K. L. Pierce, S. Saxena, and A. Pines, Proc. Natl. Acad. Sci., 2003, 100, 9122
"Laser Polarized 129-Xenon NMR and MRI at Ultralow fields," A. Wong-Foy, S. Saxena, A. J. Moule, H. M. L. Bitter, J. A. Seeley, R. M. MecDermott, J. Clarke and A. Pines, J. Magn. Reson., 2002, 157, 235
"Resolution of Xenon-129 Chemical Shifts at Ultra low Magnetic Field," S. Saxena, A. Wong-Foy, A. J. Moule, J. A. Seeley, R. McDermott, J. Clarke and A. Pines, J. Am. Chem. Soc., 2001, 123, 8133