Question

What would be the most economical way to encode for and build a viral capsid?

Answer 1

A capsid is the protein shell of a virus, enclosing genetic material. It consists of several oligomeric structural subunits made of protein called protomers. The capsids surrounds the virus and is composed of a finite number of protein subunits known as capsomers, which usually associated with or are found close to the virion nucleic acid. The essential functions of the capsid are to protect the functional integrity of the viral RNA when the virion is outside the host cell and to initiate the infectious process when a receptor on a suitable host cell is encountered.

Spiral capsid posses an icosahedral structure, while helical capsids posses an elongated capsid structure. Capsids are constituted by numerous building blocks( subunits) in that each subunit is made up of one or a few molecule of structural proteins. Although each individual structural protein is not symmetrical, the capsid made up of numerous structural proteins are symmetrical.

Viruses have adopted 'subunit assembly' as a strategy to build robust capsid structures. Conversely, the capsid needs to be dismantled eventually upon infection. In other words, the capsid is not a static shell; rather, it is a dynamic structure comprised of flexible subunits.

The genetic economy gives rise to highly symmetric structures, typically genomes that encode a maturation protein, the capsid protein and a subunit, raising the question as to how the viral capsid proteins select and interact and obtain the highest possible resolution for those capsid proteins that do they obey.

Although homologous capsid proteins are encoded by highly diverse viruses, there and viruses are the most abundant biological entitiles on earth and show. The viral capsid proteins (CPs) typically do not have obvious homologs of the virion mass, making it challenging to single out the major virion protein.