- Staff Scientist, NIDDK, NIH, 2004–Present
- Visiting Fellow, NIH, 1999–2004
- Visiting Fellow, Hebrew University of Jerusalem, 1997, 1999
- Ph.D., Institute of Chemical Kinetics and Combustion, 1996
Our goal is to develop a toolkit to extract important quantitative parameters that control the folding and dynamics of proteins and nucleic acids, as well as protein-nucleic acid interactions at the single-molecule level.
My current research focuses on the theory of single-molecule fluorescence measurements. Researchers can use single-molecule Förster resonance energy transfer (FRET) between fluorescent donor and acceptor labels attached to a protein or nucleic acid to probe a molecule’s structure, dynamics, and function. The output of these experiments is a sequence of photons of different colors (some emitted by the donor and some by the acceptor) separated by apparently random time intervals. Quantitative analysis of photon sequences requires complete understanding of the complex microscopic processes involved. We have developed a rigorous theoretical framework for the analysis of such single-molecule FRET experiments. The theory describes how conformational dynamics, diffusion of the molecule through the laser spot, shot noise, dye photophysics, and other factors influence photon statistics. Scientists in the Laboratory of Chemical Physics at the NIDDK now routinely use these methods to analyze single-molecule experiments on protein folding.
Applying our Research
Understanding protein folding, DNA/RNA dynamics, and protein-nucleic acid interactions is of utmost importance for human health. Protein misfolding could result in a number of pathologies, such as amyloid aggregation in neurodegenerative diseases and diabetes. Protein-nucleic acid interactions are the underlying mechanisms of gene expression. Understanding protein folding and the nucleic acid dynamic and protein-DNA/RNA interactions on the single-molecule level is essential for the rational design of drugs that treat a variety of human diseases.
- Oligomerization of the tetramerization domain of p53 probed by two- and three-color single-molecule FRET.
- Chung HS, Meng F, Kim JY, McHale K, Gopich IV, Louis JM.
- Proc Natl Acad Sci U S A (2017 Aug 15) 114:E6812-E6821. Abstract/Full Text
- Reversible Stochastically Gated Diffusion-Influenced Reactions.
- Gopich IV, Szabo A.
- J Phys Chem B (2016 Aug 25) 120:8080-9. Abstract/Full Text
Research in Plain Language
Biological molecules play critical roles in cells and tissues. They influence health and diseases. These molecules include proteins and nucleic acids. Researchers need information about their structure, dynamics, and function. This information will help them better understand disease processes. Scientists can study individual molecules by attaching fluorescent labels to them. These labeled molecules emit light pulses of different colors. We develop new mathematical methods to unravel the meaning of the color pattern of these pulses.