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Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids
Published on: May 4, 2018
Antimicrobial peptides derived from heme-containing proteins: hemocidins
P Mak1, K Wójcik, J Silberring
1Institute of Molecular Biology, Jagiellonian University, Mickiewicza 3, 31-120 Kraków, Poland.
Antonie Van Leeuwenhoek
|June 11, 2004
Summary
Apohemoproteins like myoglobin and cytochrome c, when stripped of heme, exhibit broad-spectrum antimicrobial activity. Specific peptide fragments retain this activity, suggesting a novel class of antimicrobials called hemocidins.
Area of Science:
- Biochemistry
- Microbiology
- Biophysics
Background:
- Heme-containing proteins, such as hemoglobin, myoglobin, and cytochrome c, are crucial in biological systems.
- While intact proteins are generally not antimicrobial, their modified forms may possess such activities.
Purpose of the Study:
- To investigate the antimicrobial potential of heme-deprived hemoproteins and their peptide fragments.
- To characterize the mechanism of action and specificity of these antimicrobial peptides.
Main Methods:
- Heme removal from myoglobin, hemoglobin, and cytochrome c.
- Enzymatic digestion of apohemoproteins to generate peptide fragments.
- Assessment of microbicidal activity against various microorganisms.
- Analysis of membrane permeabilization, cation sensitivity, and cytotoxicity assays.
Main Results:
- Heme-deprived hemoproteins (apohemoproteins) showed microbicidal activity against a broad spectrum of microorganisms at micromolar concentrations.
- Antibacterial activity was retained in peptides of approximately 50 amino acids but lost upon further fragmentation.
- The most active apomyoglobin fragment (56-131) permeabilized E. coli membranes in a salt- and cation-dependent manner.
- No lipopolysaccharide binding or hemolytic activity was observed, though slight cytotoxicity to mammalian cells occurred.
Conclusions:
- Apohemoproteins and their derived peptides possess significant antimicrobial properties, distinct from intact proteins.
- The mechanism involves membrane permeabilization, potentially via a 'carpet-like' mechanism facilitated by alpha-helical structures.
- These findings suggest a new class of antimicrobial peptides, termed 'hemocidins'.
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