Kapszidot

Kapszidot (Hungarian for capsid) refers to the protein shell that encloses the genome of a virus. It provides protection for the viral nucleic acid and plays a central role in genome packaging, recognition of host cells, and delivery of the genome into the host during infection.

Capsids are built from protein subunits called capsomeres. Their arrangement gives the capsid shape, most commonly icosahedral or helical. Some viruses have more complex, multipart assemblies. Non-enveloped (naked) viruses rely on capsids alone to protect and transmit the genome, whereas enveloped viruses have an outer lipid envelope derived from the host cell membrane that surrounds the capsid. The envelope contains viral glycoproteins that mediate attachment and entry into new host cells, while the capsid remains the core protective shell.

In icosahedral capsids, geometric principles described by the triangulation number (T) describe how many subunits form the shell. Capsid assembly is typically a self-organizing process driven by protein–protein interactions and, for some viruses, aided by scaffolding proteins or molecular motors during genome packaging.

Functionally, the capsid guards the genome from physical and chemical damage, determines the size and geometry of the virion, and participates in host recognition and entry. After the virus enters a cell, uncoating releases the genome for replication.

Research and applications include the use of virus-like particles as vaccines and platforms for nanotechnology. The term kapszidot corresponds to the Hungarian noun kapszid in its accusative form.