Advisor | Hicks, Rickey P. | en_US |
Author | Chai, Hanbo | en_US |
Date Accessioned | 2014-08-28T15:03:27Z | |
Date Available | 2016-05-11T21:42:05Z | |
Date of Issue | 2014 | en_US |
Identifier (URI) | http://hdl.handle.net/10342/4526 | |
Description | The wide application of antibiotics goes back over sixty years to the first use of penicillin in the mid-1940s. Antimicrobial agents have well-documented activity and have played a significant role in defending against various bacterial infections. However, antibiotic resistance has never ceased to undermine the efficacy of those compounds and has become a severe threat to patients with serious infections. It is imperative to discover and develop antibacterial agents with novel action mechanisms to lower the chance of drug resistance. A wide series of compounds called "antimicrobial peptides" (AMPs) have been either discovered in the nature or synthesized in laboratories around the world. The advent of AMPs has brought a new hope in the fight against the rise of antibiotic-resistant organisms. Far-UV Circular Dichroism (CD) spectroscopy and 1H NMR have been used to investigate the interactions of a series of synthetic, unnatural amino acid-containing AMPs with Lipopolysaccharide (LPS) isolated from drug resistant Gram-negative bacteria Pseudomonas aeruginosa and Klebsiella pneumoniae, along with various phospholipid compositions to better approximate the chemical makeup of the membranes of these two strains. The results showed that: (1) the binding interactions between the AMPs and the membranes are defined by the physicochemical properties of the peptide and the membrane model; (2) binding of these AMPs to the lipid A region (the innermost and phospholipid-like layer) of the LPS is stronger and dominant compared with the binding with the O-polysaccharide outer leaf moiety; (3) when different compositions of phospholipids were incorporated into the LPS to make a complete membrane model of the two strains, wavelength shifts in the CD spectra of the AMPs were observed that represents conformational changes of AMPs upon binding with the membrane model. | en_US |
Extent | 79 p. | en_US |
Format Medium | dissertations, academic | en_US |
Language | | en_US |
Publisher | East Carolina University | en_US |
Subject | Chemistry | en_US |
Subject | Antimicrobial peptides | en_US |
Subject | Circular dichroism spectroscopy | en_US |
Subject | Gram-negative bacteria | en_US |
Subject | Lipopolysaccharides | en_US |
Subject | Membrane models | en_US |
Library of Congress Subject Headings | Drug resistance in microorganisms | |
Library of Congress Subject Headings | Peptide antibiotics | |
Library of Congress Subject Headings | Pseudomonas aeruginosa | |
Library of Congress Subject Headings | Klebsiella pneumoniae | |
Title | SPECTROSCOPIC INVESTIGATIONS OF BINDING MECHANISMS BETWEEN ANTIMICROBIAL PEPTIDES AND MODELS OF THE MEMBRANES OF PSEUDOMONAS AERUGINOSA AND KLEBSIELLA PNEUMONIAE | en_US |
Type | Master's Thesis | en_US |
Department | Chemistry | en_US |
Degree | M.S. | en_US |