Enhanced Silkworm Cecropin B Antimicrobial Activity against Pseudomonas aeruginosa from Single Amino Acid Variation

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Updated: Jan 25, 2026

Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids
11:56

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

Published on: May 4, 2018

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Ottavia Romoli1, Shruti Mukherjee2, Sk Abdul Mohid2

  • 1Department of Biology , University of Padova , Via Ugo Bassi 58/B , 35131 Padova , Italy.

ACS Infectious Diseases
|May 3, 2019
PubMed

Insights

Two cecropin B isoforms from silkworms show potent antimicrobial activity against Pseudomonas aeruginosa. The Q53 CecB variant exhibits superior efficacy due to enhanced membrane interaction, offering a promising new therapeutic candidate.

Area of Science:

  • Microbiology
  • Biochemistry
  • Biophysics

Background:

  • Pseudomonas aeruginosa infections pose a significant threat, especially in vulnerable populations like cystic fibrosis patients.
  • Increasing antimicrobial resistance in P. aeruginosa necessitates the discovery of novel therapeutic agents.
  • Antimicrobial peptides (AMPs) represent a promising class of compounds for combating resistant bacterial strains.

Purpose of the Study:

  • To investigate the antimicrobial activity and mechanisms of two cecropin B (CecB) isoforms from Bombyx mori against Pseudomonas aeruginosa.
  • To compare the efficacy of the E53 CecB and Q53 CecB isoforms, which differ by a single amino acid substitution.
  • To elucidate the molecular interactions underlying the antimicrobial action of these CecB variants.

Main Methods:

  • Antimicrobial susceptibility testing and membrane-disruption assays were performed.
  • Biophysical analyses, including live-cell Nuclear Magnetic Resonance (NMR), were utilized.
  • Molecular dynamics simulations were employed to study peptide-membrane interactions.

Main Results:

  • Both E53 CecB and Q53 CecB demonstrated significant antimicrobial and membranolytic activity against P. aeruginosa.
  • The Q53 CecB isoform exhibited greater antimicrobial potency than the E53 CecB isoform.
  • Studies indicated that both peptides disrupt the bacterial outer membrane, facilitating translocation to the inner membrane, with Q53 CecB showing enhanced membrane interaction and stability.

Conclusions:

  • The single amino acid variation in Q53 CecB is crucial for its enhanced antimicrobial activity against P. aeruginosa.
  • Q53 CecB displays favorable properties, including stability and low human cell toxicity, making it a promising lead for developing new anti-P. aeruginosa therapeutics.
  • Cecropin B isoforms represent a viable strategy for developing novel antimicrobial compounds against challenging bacterial pathogens.
Keywords:
NMRantimicrobial peptidescecropin B

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