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A close look at the structure of Tobacco Mosaic
Virus.
TMV is made up of a spiral or helix of 2,130 protein (CP) subunits.
The TMV RNA, indicated in red, is about 6400 nucleotides in length. During
assembly of the TMV particle, the interaction between the CP subunits and the
RNA results in a rigid helical rod of ca. 300 nm x 18
nm. (A) Ten turns are illustrated in a side view of a small portion of a TMV
particle (B). The maximum diameter of the subunit particle is 9 nm, and the mean
diameter is 7.5 nm. The hollow core down the center is 4 nm in size. [Note: 10A
= 1 nm]
By contrast, sixty protein subunits are packed to form the protein shell of an icosahedral virus particle such as Tomato bushy stunt virus (C). The rotation symmetry is the same as the icosahedron illustrated (D). The RNA arrangement in the center of these T=3 icosahedral viruses is unknown.
Illustration from the Model of a Virus Slide Set (© APS)
© Copyright 2001 by The American Phytopathological Society
