Crystal structure of the Murray Valley encephalitis virus NS5 methyltransferase domain in complex with cap analogues

1 Oxford Protein Production Facility, The Henry Wellcome Building for Genomic Medicine, Oxford University, Roosevelt Drive, Oxford OX3 7BN, UK 2 Division of Structural Biology, The Henry Wellcome Building for Genomic Medicine, Oxford University, Roosevelt Drive, Oxford OX3 7BN, UK 3 Department of Virology, Telethon Institute for Child Health Research, University of Western Australia, Perth, WA 6008, Australia 4 CNRS, UMR2472, IFR 115, Virologie Moléculaire et Structurale, 91198 Gif sur Yvette, France 5 INRA, UMR1157, Virologie Moléculaire et Structurale, 91198 Gif sur Yvette, France Correspondence Jonathan M. Grimes jonathan{at}strubi.ox.ac.uk We have determined the high resolution crystal structure of the methyltransferase domain of the NS5 polypeptide from the Murray Valley encephalitis virus. This domain is unusual in having both the N7 and 2'-O methyltransferase activity required for Cap 1 synthesis. We have also determined structures for complexes of this domain with nucleotides and cap analogues providing information on cap binding, based on which we suggest a model of how the sequential methylation of the N7 and 2'-O groups of the cap may be coordinated. Coordinates and structure factors are deposited with the Protein Data Bank: MT1, 2px2; MT2, 2px4; MT3, 2px5; MT-GTP, 2px8; MT-GTPG, 2pxa; and MT-GTPA, 2pxc.