Cowpea chlorotic mottle virus

Cowpea Chlorotic Mottle Virus, known by the abbreviation CCMV, is a virus that specifically infects the cowpea plant, or black-eyed pea. The leaves of infected plants develop yellow spots, hence the name "chlorotic". Similar to its "brother" virus, Cowpea mosaic virus (CPMV), CCMV is produced in high yield in plants. In the natural host, viral particles can be produced at 1–2 mg per gram of infected leaf tissue. Like the majority of viruses, CCMV consists of a protein shell, that surrounds a central core of RNA. Its protein shell, or capsid, is composed of icosahedral arrangements of identical protein subunits. The symmetry at which this is done is exactly like the symmetry of a football: hexagons and pentagons are interchanged to give the final sphere. The virus is about 28 nm in size, and can be observed with transmission electron microscopy using negative staining.