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Metal ion-induced lateral aggregation of filamentous viruses fd and M13
Jay X Tang1, Paul A Janmey, Alexander Lyubartsev
1Physics Department, Indiana University, Bloomington, Indiana 47405, USA. jxtang@indiana.edu
Abstract:
We report a detailed comparison between calculations of inter-filament interactions based on Monte-Carlo simulations and experimental features of lateral aggregation of bacteriophages fd and M13 induced by a number of divalent metal ions. The general findings are consistent with the polyelectrolyte nature of the virus filaments and confirm that the solution electrostatics account for most of the experimental features observed. One particularly interesting discovery is resolubilization for bundles of either fd or M13 viruses when the concentration of the bundle-inducing metal ion Mg(2+) or Ca(2+) is increased to large (>100 mM) values. In the range of Mg(2+) or Ca(2+) concentrations where large bundles of the virus filaments are formed, the optimal attractive interaction energy between the virus filaments is estimated to be on the order of 0.01 kT per net charge on the virus surface when a recent analytical prediction to the experimentally defined conditions of resolubilization is applied. We also observed qualitatively distinct behavior between the alkali-earth metal ions and the divalent transition metal ions in their action on the charged viruses. The understanding of metal ions-induced reversible aggregation based on solution electrostatics may lead to potential applications in molecular biology and medicine.
Insights
Metal ions induce reversible aggregation of bacteriophages (fd and M13) by affecting their polyelectrolyte nature. Increased ion concentrations can lead to resolubilization, offering insights for molecular biology and medicine.
Area of Science:
- Biophysics
- Colloid and Surface Chemistry
- Computational Biology
Background:
- Bacteriophages fd and M13 exhibit polyelectrolyte characteristics.
- Divalent metal ions influence the aggregation behavior of virus filaments.
- Understanding virus aggregation is crucial for applications in molecular biology and medicine.
Purpose of the Study:
- To compare Monte Carlo simulations with experimental data on bacteriophage aggregation.
- To investigate the role of solution electrostatics in virus filament interactions.
- To explore the effect of divalent metal ions on bacteriophage aggregation and resolubilization.
Main Methods:
- Monte Carlo simulations of inter-filament interactions.
- Experimental observation of lateral aggregation of fd and M13 bacteriophages.
- Analysis of aggregation and resolubilization phenomena induced by various divalent metal ions.
Main Results:
- General findings align with the polyelectrolyte nature of virus filaments, with solution electrostatics explaining observed features.
- A key discovery is the resolubilization of virus bundles at high concentrations (>100 mM) of Mg(2+) or Ca(2+).
- Distinct behaviors were observed between alkali-earth and divalent transition metal ions regarding their interaction with charged viruses.
Conclusions:
- Solution electrostatics effectively explain metal ion-induced reversible aggregation of bacteriophages.
- The phenomenon of resolubilization at high ion concentrations provides new insights into virus assembly.
- This understanding may facilitate novel applications in molecular biology and medicine.