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Open Access Highly Accessed Research article

An enhancer peptide for membrane-disrupting antimicrobial peptides

Satoshi Ueno12, Kohtaro Kusaka1, Yasushi Tamada1, Hong Zhang1, Masaomi Minaba1 and Yusuke Kato1*

Author Affiliations

1 Division of Insect Sciences, National Institute of Agrobiological Sciences, Oowashi 1-2, Tsukuba, Ibaraki 305-8634, Japan

2 Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8572, Japan

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BMC Microbiology 2010, 10:46  doi:10.1186/1471-2180-10-46

Published: 15 February 2010

Abstract

Background

NP4P is a synthetic peptide derived from a natural, non-antimicrobial peptide fragment (pro-region of nematode cecropin P4) by substitution of all acidic amino acid residues with amides (i.e., Glu → Gln, and Asp → Asn).

Results

In the presence of NP4P, some membrane-disrupting antimicrobial peptides (ASABF-α, polymyxin B, and nisin) killed microbes at lower concentration (e.g., 10 times lower minimum bactericidal concentration for ASABF-α against Staphylococcus aureus), whereas NP4P itself was not bactericidal and did not interfere with bacterial growth at ≤ 300 μg/mL. In contrast, the activities of antimicrobial agents with a distinct mode of action (indolicidin, ampicillin, kanamycin, and enrofloxacin) were unaffected. Although the membrane-disrupting activity of NP4P was slight or undetectable, ASABF-α permeabilized S. aureus membranes with enhanced efficacy in the presence of NP4P.

Conclusions

NP4P selectively enhanced the bactericidal activities of membrane-disrupting antimicrobial peptides by increasing the efficacy of membrane disruption against the cytoplasmic membrane.