Structures of enveloped virions determined by cryogenic electron microscopy and tomography

Abstract

Enveloped viruses enclose their genomes inside a lipid bilayer which is decorated by membrane proteins that mediate virus entry. These viruses display a wide range of sizes, morphologies and symmetries. Spherical viruses are often isometric and their envelope proteins follow icosahedral symmetry. Filamentous and pleomorphic viruses lack such global symmetry but their surface proteins may display locally ordered assemblies. † These authors contributed equally.

Cytosolic delivery of nucleic acids: The case of ionizable lipid nanoparticles

“…All viruses contain nucleic‐acid genomes (RNA or DNA), which are packaged with proteins encoded by the viral genome. Viruses vary in shapes and sizes, ranging from 18 to approximately 2000 nm in diameter, and can be divided into two main categories: enveloped viruses, which have a lipid membrane (envelope) derived from the host cell; and nonenveloped viruses, lacking such membrane 101 . In this section, the strategies utilized by viruses to tackle cellular barriers in the delivery of genetic materials are discussed, and their implications in the rational design of nonviral vectors are also addressed.…”

Environmental Stability and Transmissibility of Enveloped Viruses at Varied Animate and Inanimate Interfaces

“…Conventionally, enveloped viruses are roughly spherical or ellipsoidal shaped, with some exceptions being filamentous (such as Ebola and respiratory syncytial viruses) or pleomorphic (such as arenaviruses). 29 Typically, enveloped viruses rang from 20 to 300 nm. When budding occurs, enveloped viruses acquire their lipid envelopes from the infected host cell membranes.…”

“…The lipid envelopes of enveloped viruses protect the genomes. Conventionally, enveloped viruses are roughly spherical or ellipsoidal shaped, with some exceptions being filamentous (such as Ebola and respiratory syncytial viruses) or pleomorphic (such as arenaviruses) . Typically, enveloped viruses rang from 20 to 300 nm.…”

Recent Advances in Bunyavirus Glycoprotein Research: Precursor Processing, Receptor Binding and Structure

“…The bunyavirus glycoproteins Gn and Gc (or SSP, GP1 and GP2 in the case of arenaviruses) form spikes on the lipid bilayer envelope of the virion and facilitate viral invasion of a host cell. High resolution structures of bunyavirus glycoproteins in isolation, and low resolution cryoEM studies of entire virions/VLPs, which are often pleomorphic in shape or deviate from icosahedral symmetry [ 147 ], have been predominantly limited to orthobunyaviruses, phenuiviruses, hantaviruses, tospoviruses and arenaviruses. Although these glycoproteins assemble and give rise to diverse quaternary architectures ( Figure 4 ), conserved structural features and folds have been observed within the order ( Figure 5 and Figure 6 ), with the notable exception of arenaviruses (please see Section 5.6 and Figure 7 ).…”