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Published on: August 11, 2018
Structural and Functional Characterization of a Novel Recombinant Antimicrobial Peptide from Hermetia illucens
Angela Di Somma1,2, Antonio Moretta3, Carolina Cané1
1Department of Chemical Sciences, University of Naples "Federico II", Via Cinthia 4, 80126 Napoli, Italy.
Abstract:
Antibiotics are commonly used to treat pathogenic bacteria, but their prolonged use contributes to the development and spread of drug-resistant microorganisms raising the challenge to find new alternative drugs. Antimicrobial peptides (AMPs) are small/medium molecules ranging 10-60 residues synthesized by all living organisms and playing important roles in the defense systems. These features, together with the inability of microorganisms to develop resistance against the majority of AMPs, suggest that these molecules might represent effective alternatives to classical antibiotics. Because of their high biodiversity, with over one million described species, and their ability to live in hostile environments, insects represent the largest source of these molecules. However, production of insect AMPs in native forms is challenging. In this work we investigate a defensin-like antimicrobial peptide identified in the Hermetia illucens insect through a combination of transcriptomics and bioinformatics approaches. The C-15867 AMP was produced by recombinant DNA technology as a glutathione S-transferase (GST) fusion peptide and purified by affinity chromatography. The free peptide was then obtained by thrombin proteolysis and structurally characterized by mass spectrometry and circular dichroism analyses. The antibacterial activity of the C-15867 peptide was evaluated in vivo by determination of the minimum inhibitory concentration (MIC). Finally, crystal violet assays and SEM analyses suggested disruption of the cell membrane architecture and pore formation with leaking of cytosolic material.
Insights
Researchers explored insect-derived antimicrobial peptides (AMPs) as alternatives to antibiotics. They successfully produced and characterized a novel AMP from the Hermetia illucens insect, demonstrating its potent antibacterial activity by disrupting bacterial cell membranes.
Area of Science:
- Biochemistry
- Molecular Biology
- Microbiology
Background:
- Prolonged antibiotic use drives antimicrobial resistance, necessitating novel therapeutic agents.
- Antimicrobial peptides (AMPs) are natural defense molecules with broad-spectrum activity and low resistance development potential.
- Insects are a rich source of diverse AMPs, but their production remains a challenge.
Purpose of the Study:
- To identify and characterize a novel defensin-like antimicrobial peptide from the insect Hermetia illucens.
- To develop a method for producing and purifying insect-derived AMPs for potential therapeutic applications.
Main Methods:
- Transcriptomics and bioinformatics for AMP identification.
- Recombinant DNA technology for peptide production (GST fusion).
- Affinity chromatography for purification, thrombin proteolysis for cleavage.
- Mass spectrometry and circular dichroism for structural characterization.
- Minimum inhibitory concentration (MIC) assays for antibacterial activity evaluation.
- Crystal violet and Scanning Electron Microscopy (SEM) for mechanism of action studies.
Main Results:
- A defensin-like AMP, C-15867, was identified from Hermetia illucens.
- Recombinant production and purification of C-15867 were successfully achieved.
- Structural characterization confirmed the peptide's integrity.
- C-15867 exhibited significant antibacterial activity, indicated by low MIC values.
- Mechanism of action involves disruption of bacterial cell membrane architecture and integrity.
Conclusions:
- The study successfully produced and characterized a novel insect AMP, C-15867.
- C-15867 demonstrates potent antibacterial properties via cell membrane disruption.
- Insect-derived AMPs represent promising alternatives to conventional antibiotics for combating drug-resistant bacteria.
