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Title: Interactions between magainin 2 and Salmonella typhimurium outer membranes: Effect of lipopolysaccharide structure

The role of the outer membrane and lipopolysaccharide (LPS) in the interaction between the small cationic antimicrobial peptide magainin 2 and the Gram-negative cell envelope was studied by FT-IR spectroscopy. Magainin 2 alters the thermotropic properties of the outer membrane-peptidoglycan complexes from wild-type Salmonella typhimurium and a series of LPS mutants which display differential susceptibility to the bactericidal activity of cationic antibiotics. These results are correlated with the LPS phosphorylation pattern and charge (characterized by high-resolution {sup 31}P NMR) and outer membrane lipid composition, and are compared to the bactericidal susceptibility. LPS mutants show a progressive loss of resistance to killing by magainin 2 as the length of the LPS polysaccharide moiety decreases. Disordering of the outer membrane lipid fatty acyl chains by magainin 2, however, depends primarily upon the magnitude of PLS charge rather than the length of the LPS polysaccharide. While disruption of outer membrane structure most likely is not the primary factor leading to cell death, the susceptibility of Gram-negative cells to magainin 2 is associated with factors that facilitate the transport of the peptide across the outer membrane, such as the magnitude and location of LPS charge, and concentration of LPS in the outer membrane, outermore » membrane molecular architecture, and the presence or absence of the O-antigen side chain.« less
Authors:
; ; ; ;  [1]
  1. (Ohio Univ., Athens (United States))
Publication Date:
OSTI Identifier:
5029201
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemistry; (United States); Journal Volume: 30:24
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; GLYCOPROTEINS; NUCLEAR MAGNETIC RESONANCE; LIPOPOLYSACCHARIDES; PHOSPHORYLATION; ANTIMICROBIAL AGENTS; PHOSPHORUS 31; SALMONELLA TYPHIMURIUM; TEMPERATURE DEPENDENCE; ANTI-INFECTIVE AGENTS; BACTERIA; CARBOHYDRATES; CHEMICAL REACTIONS; DRUGS; ISOTOPES; LIGHT NUCLEI; LIPIDS; MAGNETIC RESONANCE; MICROORGANISMS; NUCLEI; ODD-EVEN NUCLEI; ORGANIC COMPOUNDS; PHOSPHORUS ISOTOPES; POLYSACCHARIDES; PROTEINS; RESONANCE; SACCHARIDES; SALMONELLA; STABLE ISOTOPES 550601* -- Medicine-- Unsealed Radionuclides in Diagnostics