Stimulating antibiotic development by targeting virulence and facilitating natural product discovery

Antibiotics are a cornerstone of modern medicine and have drastically reduced the burden of infectious diseases. Unfortunately, resistance to all clinically used antibiotics has become a major challenge that is exacerbated by numerous difficulties surrounding the development of new drugs. However, inventive strategies to overcome resistance as well as discover novel antibiotics are increasingly being explored. Whereas traditional antibiotics were generally designed to directly kill as many species of bacteria as possible, several new approaches have focused on narrower spectrum agents that have significant potential benefits. Antibiotics active against only one or a small group of pathogens would spare the microbiome, which may decrease the risk of secondary infections and slow the spread of resistance. One such narrow-spectrum strategy is to target the virulence factors employed by pathogens during an infection. In chapter 2, I demonstrate that the FDA approved HIV protease inhibitor nelfinavir can be repurposed as an inhibitor of the biosynthesis of the Streptococcus pyogenes cytolytic toxin streptolysin S. Nelfinavir was utilized to explore the proteolytic processing step in streptolysin S biosynthesis and was also shown to inhibit toxin production in other pathogens known to harbor similar biosynthetic clusters. Another approach to the problem of finding new antibiotics can be found in facilitating natural product discovery. Many antibiotics are derived from natural products but continuing to find new compounds has become increasingly difficult, especially due to rediscovery of known natural products. To help circumvent this problem, I developed a probe for identifying natural products containing aldehydes and ketones from microbial extracts based on the chemical reactivity of those carbonyl functional groups (chapter 3). This method is agnostic to the activity of the product and allows for the rapid identification of low abundance compounds that may be missed through activity-based screening. I demonstrate the utility of this probe by screening a collection of bacterial extracts, leading to the discovery of an analog of the protease inhibitor antipain.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2016

Author dc:creator

• Maxson, Tucker

Contributors dc:contributor

• Mitchell, Douglas A.
• Hergenrother, Paul J.
• Burke, Martin D.
• Blanke, Steven R.

• virulence
• nelfinavir
• CaaX protease
• natural products
• reactivity based screening

Statement dc:rights

• Copyright 2016 Tucker Maxson

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/90486

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/90486