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This content will become publicly available on May 27, 2017

Title: Dynamical and phase behavior of a phospholipid membrane altered by an antimicrobial peptide at low concentration

Here we discuss that the mechanism of action of antimicrobial peptides is traditionally attributed to the formation of pores in the lipid cell membranes of pathogens, which requires a substantial peptide to lipid ratio. However, using incoherent neutron scattering, we show that even at a concentration too low for pore formation, an archetypal antimicrobial peptide, melittin, disrupts the regular phase behavior of the microscopic dynamics in a phospholipid membrane, dimyristoylphosphatidylcholine (DMPC). At the same time, another antimicrobial peptide, alamethicin, does not exert a similar effect on the DMPC microscopic dynamics. The melittin-altered lateral motion of DMPC at physiological temperature no longer resembles the fluid-phase behavior characteristic of functional membranes of the living cells. The disruptive effect demonstrated by melittin even at low concentrations reveals a new mechanism of antimicrobial action relevant in more realistic scenarios, when peptide concentration is not as high as would be required for pore formation, which may facilitate treatment with antimicrobial peptides.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [3]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. National Institute of Standards and Technology Center for Neutron Research, Gaithersburg, MD (United States); Univ. of Maryland, College Park, MD (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bhabha Atomic Research Centre, Mumbai (India)
Publication Date:
OSTI Identifier:
1259423
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 1948-7185
Publisher:
American Chemical Society
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES antimicrobial peptides; melittin; alamethicin; phosphocholine membrane; dynamics; neutron scattering; membrane-peptide interactions