Research
Research in our lab: We use (and develop) solution-state high-resolution NMR experiments combined with other biophysical techniques and computational approaches to study the conformational dynamics of proteins and nucleic acids (DNA and RNA) at atomic resolution. We believe these dynamic ensembles (and not just static structures) provide better visualization of the detailed biomolecular behavior upon getting a cellular signal.
In addition, we also use NMR spectroscopy to look at the metabolic profiles of various cells, tissues, body fluids, etc., to understand the stress response in an organism.
Collaborations: We are open to collaborations where we can apply NMR spectroscopy to study interesting systems including small molecules, supramolecules, peptides, proteins, nucleic acids, etc.
Why NMR?: NMR spectroscopy can be used to measure dynamics at atomic resolution and to deduce structural, kinetics and thermodynamic characteristics of many motional modes occurring at different time scales. NMR spectroscopy has broad sensitivity to motions spanning picosecond to second and longer timescales and can be used to characterize very subtle changes in conformation, including those involving minutely populated conformers that have exceptionally short lifetimes (on the order of nanoseconds). Last but not least, NMR spectroscopy is a powerful approach for exploring how the dynamic structure landscape is modulated by cellular cues, and time-resolved methods can be used to follow these perturbations in real-time. Click here for more details on studying dynamics by NMR.*
Further, the unique properties of NMR spectroscopy, including a high degree of reproducibility, relative ease of sample preparation, highly quantitative nature, and inherently non-destructive nature, have made it an eminent technique useful in several disciplines of metabolomics.
The basic NMR experiment can be simplistically described as follows: Nuclei behave as tiny magnets, and because of the quantization of the nuclear spin angular momentum, they align either parallel (α state) or antiparallel (β state) relative to the applied magnetic field. As the parallel (or antiparallel, depending on the nucleus) alignment is energetically more favorable, a net bulk magnetization over an ensemble of nuclei builds up parallel to the magnetic field. Radiofrequency pulses are then used to realign this bulk magnetization along a direction perpendicular to the magnetic field. The bulk magnetization then precesses about the magnetic field at a characteristic NMR frequency called the ‘chemical shift’ and gives rise to a detectable oscillating magnetic field. This non-equilibrium magnetization ultimately relaxes back to the equilibrium, parallel state. The time-domain spectrum is Fourier-transformed to yield the standard frequency-domain NMR spectrum, in which unique signals at characteristic chemi- cal shift frequencies are observed for different types of nuclei. For nucleic acid and protein applications, one is typically interested in the NMR-active nuclei 1H, 13C, 15N, 19F, 2H and 31P.*
*Reference: Nature Methods; 2011, 8(11), 919-931