STRUCTURAL STUDIES OF VIRUS ASSEMBLY - MUTAGENESIS OF MS2 COAT PROTEIN

Charlotte Axblom, Kaspars Tars and Lars Liljas

Department of Molecular Biology, Uppsala University, BMC Box 590, S-751 24 Uppsala, Sweden.
E-mail: lotta@alpha2.bmc.uu.se

Keywords: virus, coliphage, viral assembly, virus structure, MS2, mutagenesis.

MS2 is a small coliphage with an RNA genome. The virus capsid is built up of 180 chemically identical subunits of coat protein, arranged in a quasi-symmetric icosahedral shell. The RNA genome encodes four proteins, one of which is the 129 amino acids long coat protein The stucture of wild type MS2 capsid has been determined earlier (1, 2), as well as the structures of some coat protein mutants (3, 4, 5, 6). Based on these results, we have proposed a mechanism for capsid assembly. To test this theory, further mutagenesis trials seemed appropriate. The goal of the present construction of four MS2 coat protein mutants is to either confirm or reject the current hypothesis and, if a mutant unexpectedly forms capsid, to determine its structure.

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