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Characterisation of three alpha-helical antimicrobial peptides from the venom of Scorpio maurus palmatus
Patrick L Harrison1, Mohamed A Abdel-Rahman2, Peter N Strong1
1Biomedical Research Centre, Biosciences Division, Sheffield Hallam University, Sheffield, UK.
Abstract:
Scorpion venoms provide a rich source of anti-microbial peptides. Here we characterise three from the venom of Scorpion maurus palmatus. Smp13 is biologically inactive, despite sharing homology with other antimicrobial peptides, probably because it lacks a typically charged structure. Both Smp-24 and Smp-43 have broad spectrum antimicrobial activity, disrupting bacterial membranes. In addition, there is evidence that Smp24 may inhibit DNA synthesis in Bacillus subtilis. Smp24 haemolysed red blood cells but in contrast, Smp43 was non-haemolytic. The introduction of a flexible Gly-Val-Gly hinge into the middle of Smp24 did not alter the haemolytic activity of Smp24 (as might have been predicted from earlier studies with Pandinin2 (Pin2), although C-terminal truncation of Smp-24 reduced its haemolytic activity, in agreement with earlier Pin 2 studies. Smp24 and its derivatives, as well as Smp-43, were all cytotoxic (ATP release assay) toward mammalian HepG2 liver cells. Our results highlight the beneficial effect of helical-hinge-helical conformation on promoting prokaryotic selectivity of long chain scorpion AMPs, as well as the importance of examining a wide range of mammalian cell types in cytotoxicity testing.
Insights
Scorpion venom yields antimicrobial peptides. Smp-43 shows broad antimicrobial activity and is non-hemolytic, while Smp24 is hemolytic but also exhibits antimicrobial properties.
Area of Science:
- Biochemistry
- Toxicology
- Peptide Science
Background:
- Scorpion venoms are a valuable source of antimicrobial peptides (AMPs).
- Understanding the structure-activity relationships of these peptides is crucial for developing new antimicrobial agents.
Purpose of the Study:
- To characterize three antimicrobial peptides (Smp13, Smp-24, and Smp-43) from the venom of Scorpion maurus palmatus.
- To investigate the antimicrobial activity, hemolytic potential, and cytotoxicity of these peptides and their derivatives.
Main Methods:
- Peptide isolation and characterization from Scorpion maurus palmatus venom.
- Antimicrobial activity assays against bacterial strains.
- Hemolysis assays using red blood cells.
- Cytotoxicity assays using HepG2 liver cells.
- Structure-activity relationship studies involving peptide modifications (hinge insertion, truncation).
Main Results:
- Smp13 was biologically inactive due to a lack of charge.
- Smp-24 and Smp-43 demonstrated broad-spectrum antimicrobial activity by disrupting bacterial membranes.
- Smp-24 exhibited hemolytic activity and potential inhibition of DNA synthesis in Bacillus subtilis.
- Smp-43 was non-hemolytic.
- Modifications to Smp24's structure affected its hemolytic activity.
- Smp24, its derivatives, and Smp-43 were cytotoxic to HepG2 liver cells.
Conclusions:
- The helical-hinge-helical conformation is beneficial for prokaryotic selectivity in scorpion AMPs.
- Smp-43 represents a promising non-hemolytic antimicrobial peptide candidate.
- Comprehensive cytotoxicity testing across various mammalian cell types is essential.
