John C Jewett
Associate Professor, BIO5 Institute
Associate Professor, Chemistry and Biochemistry-Sci
Primary Department
Department Affiliations
(520) 626-3627
Work Summary
We seek to develop tools and strategies to expedite the understanding and treatment of the dengue virus. These advances will be transferable to other areas of virology and biochemistry. Along these lines, we are engaged in three core synergistic projects to answer the following questions: (1) Do unnatural metabolites incorporated into DENV serve as reporters for host-pathogen interactions? (2) What are the host-pathogen interactions in DENV that are targetable for diagnosis or treatment? (3) Is there a chemical reaction between two small molecules that reports on the interaction between DENV and host proteins?
Research Interest
Our goal is to merge the fields of synthetic organic chemistry with virology. We develop new reactions (and re-appropriate old ones) to gain insight into how viruses infects new host cells. Additionally, we are working to develop new methods to probe protein-protein interactions through the use of small molecules.Viruses can rapidly evolve and new tools are required to meet this ever-changing threat. While vaccinations have tamed many historically deadly viral diseases, there are still rogue viruses for which no vaccination strategy is available. Dengue virus (DENV), the virus that is responsible for dengue fever, hemorrhagic fever, and shock syndrome, is one such pathogen. The WHO estimates that the mosquito-borne pathogen infects over 50 million people each year. With a rapid increase in severe, potentially fatal, disease forms, DENV poses a significant risk to the 2.5 billion people who live in DENV endemic regions.

Publications

Gordon, C. G., MacKey, J. L., Jewett, J. C., Sletten, E. M., Houk, K. N., & Bertozzi, C. R. (2012). Reactivity of biarylazacyclooctynones in copper-free click chemistry. Journal of the American Chemical Society, 134(22), 9199-9208.

PMID: 22553995;PMCID: PMC3368396;Abstract:

The 1,3-dipolar cycloaddition of cyclooctynes with azides, also called "copper-free click chemistry", is a bioorthogonal reaction with widespread applications in biological discovery. The kinetics of this reaction are of paramount importance for studies of dynamic processes, particularly in living subjects. Here we performed a systematic analysis of the effects of strain and electronics on the reactivity of cyclooctynes with azides through both experimental measurements and computational studies using a density functional theory (DFT) distortion/interaction transition state model. In particular, we focused on biarylazacyclooctynone (BARAC) because it reacts with azides faster than any other reported cyclooctyne and its modular synthesis facilitated rapid access to analogues. We found that substituents on BARACs aryl rings can alter the calculated transition state interaction energy of the cycloaddition through electronic effects or the calculated distortion energy through steric effects. Experimental data confirmed that electronic perturbation of BARACs aryl rings has a modest effect on reaction rate, whereas steric hindrance in the transition state can significantly retard the reaction. Drawing on these results, we analyzed the relationship between alkyne bond angles, which we determined using X-ray crystallography, and reactivity, quantified by experimental second-order rate constants, for a range of cyclooctynes. Our results suggest a correlation between decreased alkyne bond angle and increased cyclooctyne reactivity. Finally, we obtained structural and computational data that revealed the relationship between the conformation of BARACs central lactam and compound reactivity. Collectively, these results indicate that the distortion/interaction model combined with bond angle analysis will enable predictions of cyclooctyne reactivity and the rational design of new reagents for copper-free click chemistry. © 2012 American Chemical Society.

Jewett, J. C., & Bertozzi, C. R. (2011). Synthesis of a fluorogenic cyclooctyne activated by Cu-free click chemistry. Organic Letters, 13(22), 5937-5939.

PMID: 22029411;PMCID: PMC3219546;Abstract:

Cyclooctyne-based probes that become fluorescent upon reaction with azides are important targets for real-time imaging of azide-labeled biomolecules. The concise synthesis of a coumarin-conjugated cyclooctyne, coumBARAC, that undergoes a 10-fold enhancement in fluorescence quantum yield upon triazole formation with organic azides is reported. The design principles embodied in coumBARAC establish a platform for generating fluorogenic cyclooctynes suited for biological imaging. © 2011 American Chemical Society.

Jewett, J. C., & Rawal, V. H. (2010). Temporary restraints to overcome steric obstacles: An efficient strategy for the synthesis of mycalamideB. Angewandte Chemie - International Edition, 49(46), 8682-8685.

PMID: 20931583;Abstract:

Restrain and release: A one-pot MukaiyamaMichael/epoxidation sequence introduced three stereocenters, an intramolecular isocyanate trapping produced a rigid 10-membered cyclic carbamate, and the selective opening of the cyclic carbamate was used to reveal the fully constructed natural product. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jensen, S. M., Nguyen, C. T., & Jewett, J. C. (2016). A gradient-free method for the purification of infective dengue virus for protein-level investigations. Journal of virological methods, 235, 125-30.

Dengue virus (DENV) is a mosquito-transmitted flavivirus that infects approximately 100 million people annually. Multi-day protocols for purification of DENV reduce the infective titer due to viral sensitivity to both temperature and pH. Herein we describe a 5-h protocol for the purification of all DENV serotypes, utilizing traditional gradient-free ultracentrifugation followed by selective virion precipitation. This protocol allows for the separation of DENV from contaminating proteins - including intact C6/36 densovirus, for the production of infective virus at high concentration for protein-level analysis.

Ahad, A. M., Jensen, S. M., & Jewett, J. C. (2013). A traceless staudinger reagent to deliver diazirines. Organic Letters, 15(19), 5060-5063.

PMID: 24059816;PMCID: PMC3857746;Abstract:

A triarylphosphine reagent that reacts with organic azides to install amide-linked diazirines is reported. This traceless Staudinger reagent reacts with complex organic azides to yield amide-linked diazirines, thus expanding the scope of the utility of both azide and diazirine chemistry. © 2013 American Chemical Society.