lipidcapsid

Lipidcapsid is not a standard term in virology. When used, it often refers to a virion that combines a lipid-containing envelope with a protein capsid surrounding the genome, i.e., an enveloped virus. In this sense, lipidcapsid-like particles describe the common architecture of many enveloped viruses, as opposed to naked virions that lack a surrounding lipid membrane.

The structure of an enveloped particle comprises an outer lipid bilayer derived from a host membrane, with viral glycoproteins embedded in the envelope. Beneath the envelope lies the nucleocapsid, a protein shell that protects the viral genome. The envelope can contain matrix or interaction proteins that connect to the nucleocapsid and help coordinate assembly. The genome can be RNA or DNA, and the capsid geometry is typically icosahedral or helical, depending on the virus family.

Biogenesis typically involves budding through a cellular membrane, during which the viral glycoproteins are synthesized and trafficked to the membrane. As new nucleocapsids assemble, they interact with the envelope to acquire the lipid membrane and glycoproteins, then complete maturation and exit the cell. The lipid envelope makes the virion more susceptible to detergents, desiccation, and some disinfectants, but it can facilitate entry into host cells via membrane fusion.

Examples of enveloped viruses include members of the Orthomyxoviridae, Coronaviridae, Herpesviridae, and Filoviridae families. The term lipidcapsid is informal and its usage varies; scientists typically refer to enveloped virions or envelopes and capsids as distinct components.