Mechanisms of selective antimicrobial activity of gaegurin 4

Heejeong Kim, Beong Jae Lee, Mun Han Lee, Seong Geun Hong, Pan Dong Ryu

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Gaegurin 4 (GGN4), an antimicrobial peptide isolated from a Korean frog, is five times more potent against Gram-positive than Gram-negative bacteria, but has little hemolytic activity. To understand the mechanism of such cell selectivity, we examined GGN4-induced K+ efflux from target cells, and membrane conductances in planar lipid bilayers. The K+ efflux from Gram-positive M. luteus (2.5 μg/ml) was faster and larger than that from Gram-negative E. coli (75 μg/ml), while that from RBC was negligible even at higher concentration (100 μg/ml). GGN4 induced larger conductances in the planar bilayers which were formed with lipids extracted from Gram-positive B. subtilis than in those from E. coli (p< 0.01), however, the effects of GGN4 were not selective in the bilayers formed with lipids from E. coli and red blood cells. Addition of an acidic phospholipid, phosphatidylserine to planar bilayers increased the GGN4-induced membrane conductance (p< 0.05), but addition of phosphatidylcholine or cholesterol reduced it (p< 0.05). Transmission electron microscopy revealed that GGN4 induced pore-like damages in M. luteus and dis-layering damages on the outer wall of E. coli. Taken together, the present results indicate that the selectivity of GGN4 toward Gram-positive over Gram-negative bacteria is due to negative surface charges, and interaction of GGN4 with outer walls. The selectivity toward bacteria over RBC is due to the presence of phosphatidylcholine and cholesterol, and the trans-bilayer lipid asymmetry in RBC. The results suggest that design of selective antimicrobial peptides should be based on the composition and topology of membrane lipids in the target cells.

Original languageEnglish (US)
Pages (from-to)39-47
Number of pages9
JournalKorean Journal of Physiology and Pharmacology
Volume13
Issue number1
DOIs
StatePublished - Feb 1 2009

Fingerprint

Escherichia coli
Lipid Bilayers
Gram-Negative Bacteria
Phosphatidylcholines
Cholesterol
Lipids
Peptides
gaegurin 4
Phosphatidylserines
Membrane Lipids
Transmission Electron Microscopy
Anura
Phospholipids
Erythrocytes
Cell Membrane
Bacteria
Membranes

Keywords

  • Antimicrobial peptide
  • Cell selectivity
  • K efflux
  • Lipid composition
  • Planar lipid bilayer

ASJC Scopus subject areas

  • Physiology
  • Pharmacology

Cite this

Mechanisms of selective antimicrobial activity of gaegurin 4. / Kim, Heejeong; Lee, Beong Jae; Lee, Mun Han; Hong, Seong Geun; Ryu, Pan Dong.

In: Korean Journal of Physiology and Pharmacology, Vol. 13, No. 1, 01.02.2009, p. 39-47.

Research output: Contribution to journalArticle

Kim, Heejeong ; Lee, Beong Jae ; Lee, Mun Han ; Hong, Seong Geun ; Ryu, Pan Dong. / Mechanisms of selective antimicrobial activity of gaegurin 4. In: Korean Journal of Physiology and Pharmacology. 2009 ; Vol. 13, No. 1. pp. 39-47.
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