Haley Bridge, an IPiB graduate student, will be defending her Ph.D. research on October 10, 2025. Her research in the Weeks Lab sought to develop a tool for site-specific modification of peptides.
Chains of amino acids — or peptides — can be engineered for therapeutic purposes, a practice widely used in hormone therapies, cancer medications, and diabetes treatments. Using site-specific modifications, peptides can be made more stable or more soluble, depending on what is needed therapeutically. Bridge’s research explored targeted modifications to tryptophan.
“Tryptophan is the least abundant amino acid,” explains Bridge. “That allows us to have a higher degree of selectivity within the peptide sequence. If we targeted a more common amino acid, there could be multiple modification sites within one peptide. Often, we’re trying to target a single site for modification.”
Bridge applied an enzyme tool dubbed 4V that can modify tryptophans in a peptide chain. She was able employ the tool to install specific modifications including modifications to antimicrobial peptides that made them more effective at killing bacteria in the lab setting, generating a fluorescent tag to track peptide uptake in living cells, and modifying the peptide endomorphin-1 to fine-tune its interaction with mu opioid receptors.
As an undergraduate student, Bridge was interested in studying bacterial genomes in search of new antibiotics. However, her interests shifted when she joined a lab and was paired with a graduate student studying post-translational modifications. She joined the Weeks Lab looking to advance her understanding of how post-translational modifications can be used to modulate peptide activity and to further develop her skills using mass spectrometry.
In her fourth year in the IPiB program, Bridge completed an internship at Promega through the UW–Madison Graduate School Industrial Internship Program. She will continue her work in the Weeks Lab as a researcher before pursuing a career in biotechnology. Bridge’s research has been published in Cell Chemical Biology and Current Protocols.
When she’s not in the lab, Bridge enjoys running, reading, and hiking. “I just try to make sure I have a nice outlet away from academia,” she says.
To learn more about Bridge’s research, attend her Ph.D. defense, “Development of chemical and enzymatic tools for site-selective peptide modification” on Friday, October 10 at 1:00 p.m. CT in Room 1211 of Hector F. DeLuca Biochemical Sciences Building.
Written by Renata Solan.