CRYSTAL STRUCTURE OF AN RNA HAIRPIN VARIANT-MS2 CAPSID COMPLEX.

Elin Grahn¹, Nicola Stonehouse², Stephanie Fonseca², Kerstin Fridborg¹, Chris Adams², Peter Stockley² and Lars Liljas¹

¹Department of Molecular Biology, Uppsala University, BMC, Box 590, SE-751 24 Uppsala, Sweden
²School of Biology, University of Leeds, Leeds LS2 9JT, United Kingdom

Keywords: MS2, RNA-hairpin, RNA-protein interaction, crystal structure

A hairpin formed within the RNA genome of the E. coli bacteriophage MS2 binds specifically to a coat protein dimer in the capsid. By soaking chemically synthesised RNA molecules into crystals of recombinant MS2 capsids, the crystal structure of the RNA-coat protein complex can be studied at high resolution. The structure of a complex between an 19 nucleotide RNA hairpin variant and the MS2 coat protein at 2.85 A resolution shows a different binding compared to the wild-type RNA hairpin-MS2 complex. The removal of one RNA-protein hydrogen bond by replacing one base in the RNA by a pyridone derivative leads to a major change in the RNA conformation at the binding site.

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