1. SJSU Undergraduate Research Grants
Identification of the Target of an
Antipyocyanin Compound in P. aeruginosa
Thu Nguyen, Laura Miller Conrad
Department of Chemistry, San Jose State University
Citations
Abstract
Synthesis SchemeEnrichable PAL Approach
Project Activities
Research Questions Acknowledgement
Antibiotic resistance is an ever worsening problem. According to the
Center for Disease Control, there were at least 2 million illnesses
caused by antibiotic resistant bacteria, resulting in at least 23,000
deaths in the U.S. per year.(1) Pseudomonas aeruginosa is an
opportunistic pathogen, meaning it infrequently causes infection in
healthy individuals but is acquired by immune-compromised
hospitalized patients.(2) While P. aeruginosa has evolved to become
more resistant to antibiotics, an antivirulence approach is a new
strategy developed to be an effective and long lasting treatment option.
Pyocyanin is a key virulence factor important to P. aeruginosa. Dr. Miller
Conrad has successfully synthesized an inhibitor for pyocyanin
production, however, its molecular target has not been identified.(3)
The purpose of my project is to develop an antipyocyanin analog with a
photoaffinity ligand and a terminal alkyne. The photoaffinity label on
the ligand has the ability to make covalent bond with the target protein
and the terminal alkyne will allow us to attach biotin to the target
protein/inhibitor complex. The target protein can then be isolated on a
streptavidin column. The protein can be characterized and identified by
mass spectrometry and proteomic analysis.
1. Antibiotic Resistance Threats in the United States, 2013
(Centers for Disease Control and Prevention).
2. Fujitani, S.; Moffett, K. S.; Yu, V. L. Pseudomonas aeruginosa.
2015, Antimicrobe.com.
3. Miller, L. C.; O’Loughlin, C. T.; Zhang, Z.; Siryaporn, A.; Silpe, J.
E.; Bassler, B. L.; Semmelhack, M. F. J. Med. Chem. 2015, 58 (3),
1298–1306.
4. O’Loughlin, C. T.; Miller, L. C.; Siryaporn, A.; Drescher, K.;
Semmelhack, M. F.; Bassler, B. L. Proc. Natl. Acad. Sci. U. S. A.
2013, 110, 17981–17986.
After studying the antipyocyanin compound’s structure and its
relationship to its antipyocyanin activity, (4) the model
compound was designed to incorporate the terminal alkyne
handle. Based on previous studies, the incorporation of the
diazirine (PAL) does not affect activity greatly. Therefore, this
compound will be tested in vivo to determine if the alkyne has
any effect on the compound’s antipyocyanin activity. If the
antipyocyanin activity remains the same as previously tested
antipyocyanin compound, we can proceed to synthesize an
enrichable PAL compound, then perform proteomics analysis to
identify its target protein, and finally perform mass spectroscopy
to verify the target protein.
Special thanks to:
- Dr. Laura Miller Conrad
- The Miller Conrad Research Group
- San Jose State University
- SJSU Undergraduate Research Grant Program
1. Will attaching a terminal alkyne to our potent
antipyocyanin compound affect its antipyocyanin activity?
2. Is blocking pyocyanin production enough to disable
pathogenicity in P. aeruginosa, allowing the host’s immune
system to clear the bacteria?
3. How is pyocyanin produced and regulated in P. aeruginosa?