Author ORCID Identifier
Document Type
Thesis
Date of Award
Spring 4-26-2024
Keywords
photo-crosslinking, peptides, membranes, lipids, tryptophan, cysteine
Degree Name
Biochemistry (BS)
Department
BIOCHEMISTRY
First Advisor
Ming An, PhD
Second Advisor
Lan Yao, PhD
Series
Science and Mathematics
Subject Heading(s)
Tryptophan--antagonists & inhibitors ; Tryptophan--analysis ; Membrane Lipids--metabolism
Abstract
Our research group has previously discovered that a Cys residue within a transmembrane (TM) helix can directly photo-crosslink to a membrane lipid via an oxythiolation addition reaction to the double bond within the lipid, with a reaction yield of 10-20%. The pH-low Insertion Peptide (pHLIP) serves as our model TM helix, while the POPC lipid bilayer is our model membrane. We had long believed that the Trp residues within the sequence of pHLIP served as the key chromophore for this reaction, and thus they were essential for the formation of the TM helix-lipid adduct. To test this hypothesis, I synthesized a negative control pHLIP variant (i.e., W9Y-W15Y-L16C-pHLIP) in which each of the Trp residues was replaced by a Tyr residue. Interestingly, my recent experiments have challenged the need for Trp in this reaction. W9Y-W15Y-L16C-pHLIP has been reproducibly shown to photo-crosslink to POPC in higher-than-expected yields of 2-9%, suggesting the possibility of there being an alternative reaction pathway. Each cross-linking reaction was monitored with HPLC. The HPLC-purified peptide-lipid adduct was characterized and quantified using UV-visible spectroscopy and LC-MS.
Recommended Citation
Telehany, Michael Jay, "Investigating the role of tryptophan in the native photo-crosslinking of a cys-containing transmembrane helix to a membrane lipid double bond" (2024). Undergraduate Honors Theses. 36.
https://orb.binghamton.edu/undergrad_honors_theses/36