1. Two in vitro, reassembled, virus-like particles produced in bacteria as imaged by AFM. (a) Helical tubes, a product of in vitro self-assembly of the Gag protein of human immunodeficiency virus.
Two in vitro, reassembled, virus-like particles produced in bacteria as imaged by AFM. (a) Helical tubes, a product of in vitro self-assembly of the Gag protein of human immunodeficiency virus. (b) Particles reassembled in vitro from a truncated form of the Gag protein from Mason-Pfizer monkey virus. (c to f) Mutant and aberrant virus particles. (c) A mutant cyanophage that lacks any protein sheath about its tail assembly and fully exposes the injection tube normally found in its interior. (d) AFM image of 3T3 cells in culture that are infected with a mutant form (gPr80gag) of Moloney murine leukemia virus. The virus, upon budding, is unable to separate completely from the host cell membrane and forms long, comet-like extensions from the cell surface. (e) A mutant of Moloney murine leukemia virus that, genetically, lacks the capacity to make envelope protein. As a consequence, it appears as a “bald” virus that exposes its limiting lipid membrane to the exterior. The undulations and variations of the membrane surface are an effect produced by local movement of the membrane in response to AFM tip pressure. (f) A crystal of brome mosaic virus. Though most of the crystal is composed of conformist T = 3 particles with the standard diameter of 30 nm, the arrows point out the presence of two exceptionally small virions, probably T = 1 icosahedra lacking RNA, and one exceptionally large virion, probably T = 4 or 7, likely containing multiple copies of RNA.
Yurii G. Kuznetsov, and Alexander McPherson Microbiol. Mol. Biol. Rev. 2011; doi: /MMBR