Sunil Saxena

Analytical, Biophysical, and Physical Chemistry

We develop pulsed electron spin resonance methods and apply them to otherwise inaccessible problems in biophysics and materials sciences. 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 develop ESR methodology that can measure distances (typically over 1‐9 nm) in spin labeled complexes. In recent years we have also developed site-directed Cu(II) labeling of proteins and nucleic acids. In proteins our methodology provides a straightforward method to elucidate biophysical information that is inaccessible to commonly used ESR labels. Examples include the direct measurement of protein backbone dynamics at β-sheet sites, and rigid Cu(II)-Cu(II) distance measurements that enable high precision in the analysis of protein structure, conformational changes, and interactions with other biomolecules. Likewise, in DNA, we have discovered a new nucleotide-independent, site-specific Cu(II) spin label that resides within the interior of the DNA helix. Cu(II) -based distance measurements directly measure the most-probable backbone distance. Additionally, we develop models for the interpretation of the ESR distance information, primarily utilizing molecular dynamics (MD) simulations. Ongoing projects in the group seek to shed light on how biomolecular dynamics and protein-DNA interactions lead to function in a metalloregulator and an endonuclease.

The students in the group are trained in the interdisciplinary interface between Chemistry and Biophysics gaining skills that range from cutting-edge spectroscopy and molecular modeling to protein mutagenesis and expression. The students are continuously challenged to gain new skills to prepare them for an everchanging professional environment. Roughly half of the alumni are in academia while the other half are in pharmaceutical industry.

Our science is highly collaborative, and we value the ability to work as a team. We emphasize the holistic training of a diverse group of students and focus on the development of both hard and soft professional skills. We invite you to visit our group website and to contact us to explore the diversity of research projects currently underway in our group.