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Postdoctoral Appointee
Education
Bachelor’s Degree: Chemical Biology, University of California Berkeley (2009-2012)
Doctoral Degree: Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine (2012-2017)
Postdoctoral Fellowships: Sandia National Laboratories (2017-present)
Research Interests
As a biochemist, Seamon’s research involves understanding how proteins—and especially enzymes—carry out their functions and contribute to cellular processes. With this knowledge, he can identify proteins that have industrial or medical uses (e.g. genome editing from CRISPR-Cas9), generate protein variants with novel properties or enhanced activity (e.g. neutralizing antibodies against pathogens), and discover inhibitors of proteins that contribute to undesirable outcomes (e.g. viral protease inhibitors).
- Fundamental Enzymology Proteins carry out every function required for the cell to replicate its genetic material, respond to environmental stimuli, and fend off viral/bacterial infection. This diverse repertoire of requirements results in proteins that are able to catalyze almost any chemical reaction you can imagine, while the need to maintain cellular homeostasis results in highly sophisticated regulation both within and between proteins. Fundamental studies allow us to unravel the catalytic mechanism of an enzyme and understand its allosteric regulation, invaluable starting points for developing protein variants for enhanced industrial utility or for the discovery of inhibitors. Relevant Publications:
- Seamon, K. J., Bumpus, N. N. & Stivers, J. T. Single-Stranded Nucleic Acids Bind to the Tetramer Interface of SAMHD1 and Prevent Formation of the Catalytic Homotetramer. Biochemistry 55, 6087–6099 (2016)
- Seamon, K. J., Sun, Z., Shlyakhtenko, L. S., Lyubchenko, Y. L. & Stivers, J. T. SAMHD1 is a single-stranded nucleic acid binding protein with no active site-associated nuclease activity. Nucleic Acids Research 43, 6486–6499 (2015)
- Development of High-Throughput Biochemical Activity Assays In order to discover and/or rationally design an inhibitor of a protein of interest, one must develop a reliable high-throughput assay of protein activity. Because many thousands of small molecules or peptides are often screened in order to identify inhibitors, we have the capability to establish colorimetric enzyme assays in 96- or 384-well plate format and rapidly carry out large library screens to identify inhibitory compounds for further development. In recent work, we developed the first high-throughput-compatible activity assay for the widely-used CRISPR-Cas9 family of enzymes. Relevant Publications:
- Seamon, K. J., Light, Y. K., Saada, E. A., Schoeniger, J. S. & Harmon, B. Versatile High-Throughput Fluorescence Assay for Monitoring Cas9 Activity. Anal. Chem. 90, 6913–6921 (2018)
- Seamon, K. J. & Stivers, J. T. A High-Throughput Enzyme-Coupled Assay for SAMHD1 dNTPase. J Biomol Screen 20, 801–809 (2015)
- E. coli and Mammalian Cell-Based Assays Although biochemical activity assays are ideal for their simplicity and easy scalability, in the vast majority of cases any novel proteins of therapeutic interest or inhibitors of naturally-occurring proteins must be effective in a more realistic cell-based environment. In order to measure enzyme activity directly in both E. coli and mammalian models, we have created engineered cell lines that either grow/die or express fluorescence proteins in response to enzyme activity. An additional advantage of such cell-based screens is that proteins/peptides can be screened as the encoding DNA libraries without the need for separate protein expression and purification.
Awards, Honors, and Memberships
American Chemical Society Member [2010 – present]
American Heart Association Pre-Doctoral Fellow [2014 – 2016]
Selected Publications
Seamon, K. J., Light, Y. K., Saada, E. A., Schoeniger, J. S. & Harmon, B. Versatile High-Throughput Fluorescence Assay for Monitoring Cas9 Activity. Anal. Chem. 90, 6913–6921 (2018)
Seamon, K. J., Bumpus, N. N. & Stivers, J. T. Single-Stranded Nucleic Acids Bind to the Tetramer Interface of SAMHD1 and Prevent Formation of the Catalytic Homotetramer. Biochemistry 55, 6087–6099 (2016)
Seamon, K. J., Sun, Z., Shlyakhtenko, L. S., Lyubchenko, Y. L. & Stivers, J. T. SAMHD1 is a single-stranded nucleic acid binding protein with no active site-associated nuclease activity. Nucleic Acids Research 43, 6486–6499 (2015)
Seamon, K. J. & Stivers, J. T. A High-Throughput Enzyme-Coupled Assay for SAMHD1 dNTPase. J Biomol Screen 20, 801–809 (2015)
Seamon, K. J. et al. Small molecule inhibition of SAMHD1 dNTPase by tetramer destabilization. J. Am. Chem. Soc. 136, 9822–9825 (2014)
Hansen, E. C., Seamon, K. J., Cravens, S. L. & Stivers, J. T. GTP activator and dNTP substrates of HIV-1 restriction factor SAMHD1 generate a long-lived activated state. Proc. Natl. Acad. Sci. U.S.A. 111, E1843–51 (2014)