Quantitative nanoscale electrostatics of viruses

Area of Science:

• Biophysics
• Virology
• Surface Science

Background:

• Electrostatic interactions are crucial for biomolecular recognition, including virus-host cell binding.
• The electric charge of viral particles significantly contributes to non-specific interactions.
• Understanding viral charge is key to deciphering infection mechanisms.

Purpose of the Study:

• To measure the electrostatic charge density of individual viruses in a liquid environment.
• To determine if charge density can serve as a distinguishing characteristic for different viruses.
• To correlate measured charge density with viral capsid structure and genetic material content.

Main Methods:

• Utilized Atomic Force Microscopy (AFM) force spectroscopy to measure electrostatic forces.
• Probed individual viral particles, including ϕ29 bacteriophage, adenovirus, and minute virus of mice.
• Analyzed force-distance curves to extract charge density information.

Main Results:

• Successfully obtained charge density values for individual viral particles.
• Observed systematic differences in charge density among the studied viruses.
• Findings align with theoretical predictions derived from X-ray structural data.

Conclusions:

• Viral charge density is a unique and distinguishing characteristic of each virus.
• Charge density is critically dependent on the viral capsid composition and the presence or absence of genetic material.
• AFM force spectroscopy provides a viable method for probing virus electrostatics.