Alkalinization of Icosahedral Non-enveloped Viral Capsid Interior Through Proton Channeling.

Small icosahedral viruses have a compact capsid that apparently lacks holes through which solvents can be exchanged with the external milieu. However, due to the steric hindrance of amino acids, upon folding, capsid proteins form narrow cavities in which water and ions can be trapped. These occluded solvent molecules can form lines of water, called water wires, representing an arrangement with special features for proton conduction. In this chapter, we review the physico-chemical principles that permit proton conduction through protein cavities. We also describe how a combination of these elements found in an insect viral capsid can allow the virus to sense alkaline environments. Through this analysis, we stress the need to combine experimental and theoretical techniques when modeling complex biological systems.

Editorial: Physical Virology and the Nature of Virus Infections.

Virus particles, 'virions', range in size from nano-scale to micro-scale. They have many different shapes and are composed of proteins, sugars, nucleic acids, lipids, water and solutes. Virions are autonomous entities and affect all forms of life in a parasitic relationship. They infect prokaryotic and eukaryotic cells. The physical properties of virions are tuned to the way they interact with cells. When virions interact with cells, they gain huge complexity and give rise to an infected cell, also known as 'virus'. Virion-cell interactions entail the processes of entry, replication and assembly, as well as egress from the infected cell. Collectively, these steps can result in progeny virions, which is a productive infection, or in silencing of the virus, an abortive or latent infection. This book explores facets of the physical nature of virions and viruses and the impact of mechanical properties on infection processes at the cellular and subcellular levels.