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High Resolution Physical Characterization of Single Metallic Nanoparticles
Published on: June 28, 2019
Alpha-hemolysin nanopore allows discrimination of the microcystins variants
Janilson J S Júnior1,2, Thereza A Soares3, Laércio Pol-Fachin3,4
1Departamento de Biofísica e Radiobiologia, Universidade Federal de Pernambuco Avenida Prof. Moraes Rego, s/n, Cidade Universitária Recife Pernambuco 50670-901 Brazil cgrufpe@gmail.com +55 81 2126 8560 +55 81 2126 8535.
Abstract:
Microcystins (MCs) are a class of cyclic heptapeptides with more than 100 variants produced by cyanobacteria present in surface waters. MCs are potent hepatotoxic agents responsible for fatal poisoning in animals and humans. Several techniques are employed in the detection of MCs, however, there is a shortage of methods capable of discriminating variants of MCs. In this work we demonstrate that the α-hemolysin (αHL) nanopore can detect and discriminate the variants (LR, YR and RR) of MCs in aqueous solution. The discrimination process is based on the analysis of the residence times of each variant of MCs within the unitary nanopore, as well as, on the amplitudes of the blockages in the ionic current flowing through it. Simulations of molecular dynamics and calculation of the electrostatic potential revealed that the variants of MCs present different charge distribution and correlated with the three patterns on the amplitudes of the blockages in the ionic current. Additionally, molecular docking analysis indicates different patterns of interaction of the variants of MCs with two specific regions of the nanopore. We conclude that αHL nanopore can discriminate variants of microcystins by a mechanism based mainly on electrostatic interaction. Finally, we propose the use of nanopore-based technology as a promising method for analyzing microcystins in aqueous solutions.
Insights
This study shows how α-hemolysin (αHL) nanopores can distinguish between microcystin (MC) variants. This advancement offers a new way to detect these harmful cyanotoxins in water.
Area of Science:
- Environmental Science
- Analytical Chemistry
- Biotechnology
Background:
- Microcystins (MCs) are toxic cyclic heptapeptides produced by cyanobacteria, posing risks to aquatic ecosystems and human health.
- Existing detection methods for MCs often lack the ability to differentiate between specific variants.
- The need for advanced analytical techniques to identify and quantify diverse MC variants is critical.
Purpose of the Study:
- To demonstrate the capability of the α-hemolysin (αHL) nanopore for detecting and discriminating between microcystin variants (MC-LR, MC-YR, MC-RR).
- To investigate the underlying mechanisms of discrimination based on nanopore interaction.
- To propose nanopore-based technology as a novel analytical tool for microcystin analysis.
Main Methods:
- Utilized α-hemolysin (αHL) nanopore sensing to analyze microcystin variants in aqueous solutions.
- Analyzed residence times and ionic current blockage amplitudes within the nanopore.
- Employed molecular dynamics simulations and electrostatic potential calculations.
- Performed molecular docking analysis to study variant-nanopore interactions.
Main Results:
- The αHL nanopore successfully detected and discriminated between MC-LR, MC-YR, and MC-RR variants.
- Discrimination was achieved by analyzing differences in residence times and blockage amplitudes.
- Molecular dynamics and docking revealed distinct charge distributions and interaction patterns for each variant.
- Results showed a correlation between electrostatic interactions and observed blockage patterns.
Conclusions:
- The αHL nanopore can effectively discriminate between microcystin variants based primarily on electrostatic interactions.
- Nanopore-based technology presents a promising and sensitive method for analyzing microcystins in aquatic environments.
- This approach offers a significant advancement in the detection and differentiation of harmful algal bloom toxins.
