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Updated: Aug 13, 2025
A Calcium Bioluminescence Assay for Functional Analysis of Mosquito Aedes aegypti and Tick Rhipicephalus microplus G Protein-coupled Receptors
Published on: April 20, 2011
Bactericidal Properties of Proline-Rich Aedes aegypti Trypsin Modulating Oostatic Factor (AeaTMOF)
Dov Borovsky1, Pierre Rougé2, Robert G Shatters3
1Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
Abstract:
The antimicrobial properties of proline-rich Aedes aegypti decapeptide TMOF (AeaTMOF) and oncocin112 (1-13) were compared. Incubations with multidrug-resistant Escherichia coli cells showed that AeaTMOF (5 mM) was able to completely inhibit bacterial cell growth, whereas oncocin112 (1-13) (20 mM) partially inhibited bacterial growth as compared with bacterial cells that were not multidrug-resistant cells. AeaTMOF (5 mM) was very effective against Acinetobacter baumannii and Pseudomonas aeruginosa, completely inhibiting cell growth during 15 h incubations. AeaTMOF (5 mM) completely inhibited the Gram-positive bacteria Staphylococcus aureus and Bacillus thurengiensis sups. Israelensis cell growth, whereas oncocin112 (1-13) (10 and 20 mM) failed to affect bacterial cell growth. E. coli cells that lack the SbmA transporter were inhibited by AeaTMOF (5 mM) and not by oncocin112 (1-13) (10 to 20 mM), indicating that AeaTMOF can use other bacterial transporters than SbmA that is mainly used by proline-rich antimicrobial peptides. Incubation of E. coli cells with NaAzide showed that AeaTMOF does not use ABC-like transporters that use ATP hydrolysis to import molecules into bacterial cells. Three-dimensional modeling and docking of AeaTMOF to SbmA and MdtM transporters showed that AeaTMOF can bind these proteins, and the binding location of AeaTMOF inside these protein transporters allows AeaTMOF to be transported into the bacterial cytosol. These results show that AeaTMOF can be used as a future antibacterial agent against both multidrug-resistant Gram-positive and -negative bacteria.
Insights
The novel antimicrobial peptide AeaTMOF effectively inhibits multidrug-resistant Gram-positive and Gram-negative bacteria, including E. coli and Acinetobacter baumannii. Unlike other peptides, AeaTMOF utilizes alternative transporters for bacterial entry, offering a promising new antibacterial agent.
Area of Science:
- Antimicrobial Peptides
- Bacterial Physiology
- Drug Discovery
Background:
- Proline-rich antimicrobial peptides (PR-AMPs) are crucial in innate immunity.
- The mosquito peptide AeaTMOF and oncocin112 were investigated for their antimicrobial spectrum and mechanisms.
- Understanding peptide-bacterial transporter interactions is key to developing new antibiotics.
Purpose of the Study:
- To compare the antimicrobial efficacy of Aedes aegypti decapeptide TMOF (AeaTMOF) and oncocin112 (1-13).
- To elucidate the bacterial uptake mechanisms of AeaTMOF.
- To assess the potential of AeaTMOF as a novel antibacterial agent against multidrug-resistant pathogens.
Main Methods:
- Comparative antimicrobial assays against multidrug-resistant Gram-negative (E. coli, A. baumannii, P. aeruginosa) and Gram-positive (S. aureus, B. thuringiensis) bacteria.
- Bacterial growth inhibition assays using E. coli strains with and without the SbmA transporter.
- Assessment of AeaTMOF uptake mechanism using NaAzide inhibition of ABC-like transporters.
- Three-dimensional modeling and molecular docking of AeaTMOF to bacterial transporters (SbmA, MdtM).
Main Results:
- AeaTMOF (5 mM) demonstrated potent antimicrobial activity, completely inhibiting E. coli, A. baumannii, P. aeruginosa, S. aureus, and B. thuringiensis.
- Oncocin112 showed weaker activity, only partially inhibiting multidrug-resistant E. coli and failing to inhibit Gram-positive bacteria.
- AeaTMOF effectively inhibited E. coli lacking the SbmA transporter, suggesting alternative uptake pathways.
- AeaTMOF does not utilize ATP-dependent ABC-like transporters for entry.
- Molecular modeling indicated AeaTMOF can bind to SbmA and MdtM transporters, facilitating translocation into the bacterial cytosol.
Conclusions:
- AeaTMOF exhibits broad-spectrum antimicrobial activity against clinically relevant multidrug-resistant bacteria.
- AeaTMOF employs distinct bacterial uptake mechanisms compared to other PR-AMPs, bypassing the SbmA transporter.
- AeaTMOF represents a promising candidate for the development of novel antibacterial therapeutics.
