Reoviruses resolution

Where the structure of one or more similar viruses is available, low-resolution starting phases can be calculated from the model virus (or summed structures) correctly placed in the cell of the unknown structure (Fry et al., 1993). Cryo-EM reconstructions can provide adequate starting phases and envelope information for the determination of novel structures, for example BTV (Grimes effl/., 1998), Reovirus... 

Centonze, V. E., Chen, Y., Severson, T. J., Borisy, G. G., and Nibert, M. L. (1995). Visualization of single reovirus particles by low-temperature, high-resolution scanning electron microscopy./. Struct. Biol. 115, 215-225. 

The analysis of icosahedral structures now routinely reaches 10 A resolution and in the better cases is approaching the level achieved for 2D crystals and helical assemblies. This is, in part, due to the 60-fold redundancy of information, which means that each single particle image is equivalent to 60 particles with no symmetry. At the present time good results (6-8 A) have been achieved for rice dwarf virus, hepatitis B virus and reovirus (Figure 2.7), enabling alpha helices to be traced. 

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