Related Experiment Video

Updated: Jan 16, 2026

Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids
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Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids

Published on: May 4, 2018

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Single Amino Acid Modulates Antimicrobial Peptide Cooperativity between LL-37 and HNP1

Ariane M Schwitter1, Takashi Yasuda2, Xiang Li2

  • 1Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba Meguro-Ku, Tokyo 153-8505, Japan.

Langmuir : the ACS Journal of Surfaces and Colloids
|January 15, 2026
PubMed

Insights

Human antimicrobial peptides (AMPs) like LL-37 and defensins show synergistic effects against resistant bacteria. Defensin N-termini are key to this cooperative interaction, enhancing bacterial killing and reducing host toxicity.

Area of Science:

  • Biochemistry
  • Microbiology
  • Structural Biology

Background:

  • Antimicrobial peptides (AMPs) are crucial in combating multidrug-resistant bacterial infections.
  • Human AMPs LL-37 and α-defensin (HNP1) demonstrate synergistic activity, enhancing bacterial killing and reducing host cell toxicity.
  • The structural basis for this cooperative phenomenon between LL-37 and defensins is not well understood.

Purpose of the Study:

  • To investigate the structural-function relationship underlying the cooperative effect between LL-37 and various defensins.
  • To determine if the observed cooperative effect between LL-37 and HNP1 is specific or extends to other defensin family members.
  • To identify specific regions within defensins responsible for modulating the synergistic interaction with LL-37.

Main Methods:

  • Membrane toxicity assays were performed to assess the interaction between LL-37 and different defensins (HNP1, HNP3, HNP4, hBD1, HNP2).
  • Comparative analysis of amino acid sequences of various defensins was conducted.
  • Structure-activity relationship studies focused on the N-terminal regions of defensins.

Main Results:

  • The cooperative effect of LL-37 neutralization against POPC membranes by HNP1 was observed with HNP3, HNP4, and hBD1, but not HNP2.
  • The N-terminal region of defensins was identified as a critical modulator of the cooperative effect with LL-37.
  • Specific amino acid variations in the N-terminus correlated with the presence or absence of the synergistic interaction.

Conclusions:

  • The cooperative interaction between LL-37 and defensins is not limited to HNP1 but is a broader property of certain defensin family members.
  • The N-terminus of defensins plays a pivotal role in mediating the synergistic antimicrobial activity and reduced cytotoxicity when combined with LL-37.
  • Understanding this structural-function relationship can guide the development of novel AMP-based therapeutics.

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