Assistant Professor of Chemistry
: Dana 223
- A.B. 1999, Occidental College
- Ph.D. 2007, Yale University
- Postdoctoral Associate, 2007-2010, Yale University
At Skidmore since 2010
Affiliated Faculty, RNA Institute, SUNY-Albany
My research group is interested in the different pathways organisms use to translate the genetic code, in particular with regard to the amino acid asparagine (Asn). To translate Asn codons requires forming the adapter molecule asparaginyl-transfer RNA (Asn-tRNA). In eukaryotes and a number of prokaryotes, Asn is directly attached to its tRNA (tRNAAsn
) by asparaginyl-tRNA synthetase (AsnRS). Many prokaryotes do not encode AsnRS in their genomes and instead synthesize Asn on its tRNA in a two-step pathway. First an aspartyl-tRNA synthetase attaches the amino acid aspartate (Asp) to tRNAAsn
. The Asp on the tRNA is then amidated to Asn by the amidotransferase GatCAB to form Asn-tRNAAsn
used in protein synthesis. A number of bacteria, including known human pathogens, appear to encode both routes for making Asn-tRNAAsn
. We are interested in determining if this is the case and if so how these organisms use both pathways. The work will provide insight not only into the life cycles of these bacteria but also into the evolution of the Asn decoding pathways. We are also investigating using the two-step pathway to expand the genetic code to incorporate unnatural amino acids into proteins.
- CH 106 Chemical Principles II
- CH 341 Biochemistry: Macromolecular Structure & Function
- CH 342 Biochemistry: Intermediary Metabolism
- CH 377/378 Senior Seminar in Chemistry and Biochemistry
- SSP 100 Scribner Seminar-Coming of Age:Food, Drugs and Sex after the Biotech Revolution
- O'Donoghue, P., Sheppard, K., Nureki, O., and Söll, D. (2011) Rational design of an evolutionary precursor of glutaminyl-tRNA synthetase. Proc. Natl. Acad. Sci. U.S.A. 108, 20485-20490.
- Englert, M., Sheppard, K., Aslanian, A., Yates III, J., and Söll, D. (2011) Archaeal 3'-phosphate RNA splicing ligase characterization identifies the missing component in tRNA maturation. Proc. Natl. Acad. Sci. U.S.A. 108, 1290-1295.
- Englert, M., Sheppard, K., Gundllapalli, S., Beier, H., and Söll, D. (2010) Branchiostoma floridae has separate healing and sealing enzymes for 5'-phosphate RNA ligation. Proc. Natl. Acad. Sci. U.S.A. 107, 16834-16839.
- Rampias, T.*, Sheppard K.*, and Söll, D. (2010) The archaeal transamidosome for RNA-dependent glutamine biosynthesis. Nucleic Acids Res. 38, 5774-5783.
- Wu, J., Bu, W., Sheppard, K., Kitabatake, M., Kwon, S-T., Söll, D., and Smith, J.L. (2009) Insights into tRNA-dependent amidotransferase evolution and catalysis from the structure of the Aquifex aeolicus enzyme. J. Mol. Biol. 391, 703-716.
- Sheppard, K., Sherrer, R.L., and Söll, D. (2008) Methanothermobacter thermautotrophicus tRNAGln confines the amidotransferase GatCAB to asparaginyl-tRNAAsn formation. J. Mol. Biol. 377, 845-853.
- Sheppard, K., and Söll, D. (2008) On the evolution of the tRNA-dependent amidotransferases, GatCAB and GatDE. J. Mol. Biol. 377, 831-844.
- Sheppard, K.*, Yuan, J.*, Hohn, M.J., Jester, B., Devine, K., and Söll, D. (2008) From one amino acid to another: tRNA-dependent amino acid biosynthesis. Nucleic Acids Res. 36, 1813-1825.
- Sheppard, K., Akochy, P.M., and Söll, D. (2008) Assays for transfer RNA-dependent amino acid biosynthesis. Methods 44, 139-145.
- Sheppard, K.*, Akochy, P.M.*, Salazar, J.C., and Söll, D. (2007) The Helicobacter pylori amidotransferase GatCAB is equally efficient in glutamine-dependent transamidation of Asp-tRNAAsn and Glu-tRNAGln. J. Biol. Chem. 282, 11866-11873.
- Oshikane, H.*, Sheppard, K.*, Fukai, S., Nakamura, Y., Ishitani, R., Numata, T., Sherrer, R.L., Feng, L., Schmitt, E., Panvert, M., Blanquet, S., Mechulam, Y., Söll, D., and Nureki, O. (2006) Structural basis of RNA-dependent recruitment of glutamine to the genetic code. Science 312, 1950-1954.
* denotes authors contributed equally to this work.
- American Association for the Advancement of Science
- American Chemical Society
- American Society for Biochemistry and Molecular Biology
- American Society for Microbiology
- Council on Undergraduate Research
- New York Academy of Sciences