Mechanism of Thioredoxin Reductase -- a Collaborative Project
Dr. Hondal received his Ph.D. in Chemistry from the Ohio State University in 1997. He then spent one year in the laboratory of Raymond Burk at Vanderbilt University studying the chemistry of selenomethionine and the structure of selenoprotein P. He continued his postdoctoral study under the direction of Ronald Raines at the University of Wisconsin-Madison as a NIH Postdoctoral Fellow. His work there focused on state of the art protein engineering techniques, including native chemical ligation and expressed protein ligation. His postdoctoral work at UW-Madison focused on methods for inserting non-natural amino acids into proteins as a means of addressing important structure-function questions in enzymology.
There are two main areas of research in my lab. First, we are concerned with the mechanistic enzymology of high molecular weight thioredoxin reductases. The mammalian form of this enzyme contains the rare amino acid selenocysteine. One focus of this project is to understand why the mammalian enzyme requires this rare amino acid, while other homologues from C. elegans and D. melanogaster contain a conventional cysteine residue instead. We use protein engineering and protein semisynthesis techniques to study these enzymes. Semisynthesis allows us to insert a number of non-natural amino acids into the enzyme, as well as produce the mammalian form of the enzyme containing selenocysteine. X-ray crystallography, NMR spectroscopy, peptide synthesis, and steady-state kinetics are all techniques emphasized in my laboratory.
A second project involves developing new methods for regioselective disulfide bond formation in peptides and small proteins. A large challenge for peptide chemists is correctly pairing half-cystinyl residues. This is achieved through orthogonal protection/deprotection schemes using multiple protecting groups for the sulfhydryl group of cysteine. These groups are then selectively removed one at a time to form the correct disulfide bond.
Eckenroth, BE, Lacey, BM, Lothrop, AP, Harris, KM, and Hondal RJ (2007) Investigation of the C-termindal Redox Center of High Mr Thioredoxin Reductases by Protein Engineering and Semisynthesis. Biochemistry In Press
Eckenroth, BE, Rould, MA, Hondal,RJ, and Everse SJ (2007) Structural and Biochemical Studies Reveal Differences in the Catalytic Mechanisms of Mammalian and Drosophila melanogaster Thioredoxin Reductases. Biochemistry 46, 4694-4705
Harris, KM, Flemer, S, and Hondal RJ (2007) Studies on deprotection of cysteine and selenocysteine side chain protecting groups. J. Pept. Sci 13, 81-93
Flemer, SJ, Lacey, BM and Hondal RJ. (2007). Synthesis of peptide substrates for mammalian thioredoxin reductase. J. Pept. Sci. 14(5):637-47
Eckenroth BE, Harris, K, Turanov, AA, Gladyshev, VN, Raines, RT, and Hondal, RJ (2006) Semisynthesis and characterization of mammalian thioredoxin reductase Biochemistry 45, 5158-5170.
Harris, KM and Hondal RJ. (2006) Deprotection of the p-methoxybenzyl group of selenocysteine by neighboring group participation. In Understanding Biology Using Peptides: Proceedings of the 19th American Peptide Symposium (Sylvie E. Blondelle, Ed.). Springer, New York, pgs 91-92.
Lacey, BM and Hondal, RJ (2006) Characterization of Mitochondrial Thioredoxin Reductase from C. elegans. Biochem. Biophys. Res. Commun. 346, 629-636.
* indicates equal contribution
Randall MJ, Spiess PC, Hristova M, Hondal RJ, van der Vliet A (2013) Acrolein-induced activation of mitogen-activated protein kinase signaling is mediated by alkylation of thioredoxin reductase and thioredoxin 1. Redox Biol 1(1): 265-75.
Cunniff B, Snider GW, Fredette N, Hondal RJ, Heintz NH (2013) A direct and continuous assay for the determination of thioredoxin reductase activity in cell lysates. Anal Biochem 443(1): 34-40.
Snider GW, Ruggles E, Khan N, Hondal RJ (2013) Selenocysteine confers resistance to inactivation by oxidation in thioredoxin reductase: comparison of selenium and sulfur enzymes. Biochemistry 52(32): 5472-81.
Chandler JD, Nichols DP, Nick JA, Hondal RJ, Day BJ (2013) Selective metabolism of hypothiocyanous acid by mammalian thioredoxin reductase promotes lung innate immunity and antioxidant defense. J Biol Chem 288(25): 18421-8.
Hondal RJ, Marino SM, Gladyshev VN (2013) Selenocysteine in thiol/disulfide-like exchange reactions. Antioxid Redox Signal 18(13): 1675-89.
Schroll AL, Hondal RJ, Flemer S Jr (2012) The use of 2,2'-dithiobis(5-nitropyridine) (DTNP) for deprotection and diselenide formation in protected selenocysteine-containing peptides. J Pept Sci 18(3): 155-62.
Schroll AL, Hondal RJ, Flemer S Jr (2012) 2,2'-Dithiobis(5-nitropyridine) (DTNP) as an effective and gentle deprotectant for common cysteine protecting groups. J Pept Sci 18(1): 1-9.
The Paul D. Boyer Memorial Award for Post-Doctoral Fellows (2001)
Best Publication Award, Journal of Peptide Science The prize is awarded by the Editorial Board of the Journal of Peptide Science to the communicating author for a paper published in the 2007-2009 time period in the Journal of Peptide Science. (2009)
Department of Biochemistry
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