Fibre diffraction in the analysis of filamentous virus structure
In many plant and bacterial viruses, a filamentous nucleocapsid makes up the entire virus particle. These viruses usually form fibres naturally, but they do not crystallize. Fibre diffraction has therefore been the method of choice for structural studies, aided in recent years by cryo-electron microscopy (EM) and solid state nuclear magnetic resonance (ssNMR). Filamentous viruses, particularly tobacco mosaic virus (TMV), have been important in developing fibre diffraction methods, and fibre diffraction allowed TMV to be among the first virus structures determined. Structures of several viruses related to TMV and several filamentous bacterial viruses have been determined at resolutions of 3 Å or better, and lower resolution structures have been determined by fibre diffraction, sometimes in conjunction with other methods, for many other, unrelated, filamentous viruses.