The bacteriophage MS2
Bacteriphage MS2 is a small RNA virus which lives on male E. coli cells. It belongs to a group of small RNA phages, which are convenient model systems for the study of viral attachment to host cells, genetic control and virus assembly.
The icosahedral protein shell is composed of 180 copies of the coat protein, 129 amino acids, and one copy of the A protein, 393 amino acids. The exact location of the A- protein is not known, but immunological experiments indicate that it is exposed on the surface of the virion.
The structure of the icosahedral bacteriophage MS2 has been determined to 2.8 A resolution. The phase determination involved both molecular replacement at low resolution using a known structure and heavy-atom substitution.
The tertiary structure and topology of MS2 coat protein is unlike that of other icosahedral viruses.
