The Varga lab focuses on the biophysical characterization of protein structure and function. We use NMR and other spectroscopic techniques to investigate protein structure, protein-protein, and protein-ligand interactions. Another major research interest is the design and characterization of chiral nanoparticles. Ongoing projects include:
Antifreeze proteins are found in a wide range of cold adapted organisms, and they contribute to their freeze resistance. Antifreeze proteins adsorb to the ice surface and inhibit the growth of ice crystals. The goal of this project is to investigate the mechanism by which antifreeze proteins protect against the damage typically inflicted by cold, including the underlying molecular mechanism of ice-binding. This project is supported by NASA-EPSCoR and NIH.
Quantum dots (QDs) are nanometer size semiconductor crystals with excellent and tunable electronic and optical properties. Colloidal quantum dots consist of an inorganic semiconductor core (e.g. CdSe) and an organic capping ligand shell (e.g. cysteine). We aim to determine how chiral organic ligands induce chiroptical activity in achiral semiconductor QDs and how QDs can be used to enhance the chiroptical signal of biomolecules. Chiral QDs are promising candidates for bioimaging, biosensing, environmental nanoassays, catalysis, and chiral memory. his project was supported by NSF.
REGULATORS OF G-PROTEIN SIGNALING PROTEINS
The discoveries of a class of intracellular regulatory proteins known as regulators of G-protein signaling (RGS) proteins that mediate GPCR signaling via protein-protein interactions between the RGS domains and the gamma-subunit of G-proteins and their covalent inhibitors have opened a new venue for allosteric targeting in GPCRs. We are studying inhibitor-induced structural perturbations using NMR and MD analyses of the RGS8 protein and its mutant forms to understand the role of cysteine residues in affecting potency and specificity of inhibitors. This project is supported by NIH.
RATES OF PROTEIN EVOLUTION
We aim to identify the factors that have an important impact on the rates of protein evolution and elucidate the reasons why these factors affect rates of evolution. During evolution, different proteins accumulate amino acid changes at enormously different rates as a result of the different selective pressures to which they are subjected. This project is supported by NSF.
BACTERIAL MECHANISMS IN ESTABLISHING AND MAINTAINING CELL POLARITY
The polar organizing protein Z (PopZ) is necessary for the formation of three-dimensional microdomains at the cell poles in Caulobacter crescentus, where it functions as a hub protein that recruits multiple regulatory proteins from the cytoplasm. Although a large portion of the protein is predicted to be natively unstructured, in reconstituted systems PopZ can self-assemble into a macromolecular scaffold that directly binds to at least ten different proteins. We have utilized NMR spectroscopy to study its interaction with its binding partners. This project was supported by NIH.
- BCHM 851: Principles of Biochemistry I
- BCHM/BMCB 850/750: Physical Biochemistry
- BCHM/BMCB 851/751: Principles of Biochemistry I
- BMCB 658: General Biochemistry
- BMCB 658/658A: General Biochemistry
- BMCB 751: Principles of Biochemistry
- BMCB 799H: Honors Senior Thesis
- INCO 590: Student Research Experience
- MCBS 999: Doctoral Thesis
Kwon, Y. H., Joh, Y. A., Leonard, B. M., Balaz, M., & Varga, K. (2023). Threonine functionalized colloidal cadmium sulfide (CdS) quantum dots: The role of solvent and counterion in ligand induced chiroptical properties.. J Colloid Interface Sci, 642, 771-778. doi:10.1016/j.jcis.2023.03.177
Andrzejczyk, J., Jovic, K., Brown, L. M., Pascetta, V. G., Varga, K., & Vashisth, H. (2022). Molecular interactions and inhibition of the SARS-CoV-2 main protease by a thiadiazolidinone derivative. PROTEINS-STRUCTURE FUNCTION AND BIOINFORMATICS, 90(11), 1896-1907. doi:10.1002/prot.26385
Sreter, J. A., Foxall, T. L., & Varga, K. (2022). Intracellular and Extracellular Antifreeze Protein Significantly Improves Mammalian Cell Cryopreservation. BIOMOLECULES, 12(5). doi:10.3390/biom12050669
Jevtic, P., Elliott, K. W., Watkins, S. E., Sreter, J. A., Jovic, K., Lehner, I. B., . . . Varga, K. (2022). An insect antifreeze protein from Anatolica polita enhances the cryoprotection of Xenopus laevis eggs and embryos. JOURNAL OF EXPERIMENTAL BIOLOGY, 225(4). doi:10.1242/jeb.243662
Kwon, Y. H., Tannir, S., Balaz, M., & Varga, K. (2022). Apple juice and red wine induced mirror-image circular dichroism in quantum dots. CHIRALITY, 34(1), 70-76. doi:10.1002/chir.23380
Hagemann, N., Joseph, S., Schmidt, H. -P., Kammann, C. I., Harter, J., Borch, T., . . . Kappler, A. (2017). Organic coating on biochar explains its nutrient retention and stimulation of soil fertility. NATURE COMMUNICATIONS, 8. doi:10.1038/s41467-017-01123-0
Holmes, J. A., Follett, S. E., Wang, H., Meadows, C. P., Varga, K., & Bowman, G. R. (2016). Caulobacter PopZ forms an intrinsically disordered hub in organizing bacterial cell poles. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 113(44), 12490-12495. doi:10.1073/pnas.1602380113
Choi, J. K., Haynie, B. E., Tohgha, U., Pap, L., Elliott, K. W., Leonard, B. M., . . . Balaz, M. (2016). Chirality Inversion of CdSe and CdS Quantum Dots without Changing the Stereochemistry of the Capping Ligand. ACS NANO, 10(3), 3809-3815. doi:10.1021/acsnano.6b00567
Tohgha, U., Deol, K. K., Porter, A. G., Bartko, S. G., Choi, J. K., Leonard, B. M., . . . Balaz, M. (2013). Ligand Induced Circular Dichroism and Circularly Polarized Luminescence in CdSe Quantum Dots. ACS NANO, 7(12), 11094-11102. doi:10.1021/nn404832f
Tohgha, U., Varga, K., & Balaz, M. (2013). Achiral CdSe quantum dots exhibit optical activity in the visible region upon post-synthetic ligand exchange with D- or L-cysteine. CHEMICAL COMMUNICATIONS, 49(18), 1844-1846. doi:10.1039/c3cc37987f
Most Cited Publications