Publication Date
2025
Document Type
Dissertation/Thesis
First Advisor
Lurio, Laurence B.
Degree Name
Ph.D. (Doctor of Philosophy)
Legacy Department
Department of Physics
Abstract
To understand the mechanism by which anti-microbial peptide penetrates biological membranes,the study uses artificial supported lipid bilayers (SLBs) deposited on solid substrates. These bilayers were prepared from a lipid mixture of 1,2-dimyristoyl-sn-glycero-3- phosphocholine (DMPC)and 1,2-dimyristoyl-sn-glycero-3-phospho-(1’-rac-glycerol (DMPG) in a 10:1 molar ratio and were incubated both with and without indolicidin. Additionally, bilayers were studied after incubation with a labeled form of indolicidin, which involved attaching a 1.8 nm diameter gold nanoparticle to the peptide’s terminal arginine group.
X-ray reflectivity (XRR) was employed to identify structural differences between SLBsincubated with indolicidin and those without it. The introduction of gold labeling facilitated the determination of the vertical position of indolicidin within the bilayer using standing wave x-ray fluorescence (SWXF). The SWXF results indicated that the peptide’s depth of penetration into the bilayer varies depending on the concentration of indolicidin used during incubation, with higher concentrations leading to deeper penetration. Notably, lipid bilayers formed from liposomes incubated with 10 μM gold-labeled indolicidin demonstrated greater penetration into the bilayer than those incubated with 5 or 2 μM solutions.
The study’s findings demonstrate how both the structural integrity and penetrative behaviorof the lipid bilayer can be influenced by the concentration and labeling of indolicidin, providing insight into the peptide’s mechanism of action on membranes.
Recommended Citation
Basnet, Gobind, "X-Ray Standing-Wave Fluorescence Study of the Interaction of an Anti-Microbial Peptide with a Supported Phospholipid Bilayer" (2025). Graduate Research Theses & Dissertations. 8049.
https://huskiecommons.lib.niu.edu/allgraduate-thesesdissertations/8049
Extent
96 pages
Language
en
Publisher
Northern Illinois University
Rights Statement
In Copyright
Rights Statement 2
NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.
Media Type
Text
