title: Flaviviral methyltransferase/RNA interaction: structural basis for enzyme inhibition.
abstract: Flaviviruses are the causative agents of severe diseases such as Dengue or Yellow fever. The replicative machinery used by the virus is based on few enzymes including a methyltransferase, located in the N-terminal domain of the NS5 protein. Flaviviral methyltransferases are involved in the last two steps of the mRNA capping process, transferring a methyl group from S-adenosyl-L-methionine onto the N7 position of the cap guanine (guanine-N7 methyltransferase) and the ribose 2'O position of the first nucleotide following the cap guanine (nucleoside-2'O methyltransferase). The RNA capping process is crucial for mRNA stability, protein synthesis and virus replication. Such an essential function makes methyltransferases attractive targets for the design of antiviral drugs. In this context, starting from the crystal structure of Wesselsbron flavivirus methyltransferase, we elaborated a mechanistic model describing protein/RNA interaction during N7 methyl transfer. Next we used an in silico docking procedure to identify commercially available compounds that would display high affinity for the methyltransferase active site. The best candidates selected were tested in vitro to assay their effective inhibition on 2'O and N7 methyltransferase activities on Wesselsbron and Dengue virus (Dv) methyltransferases. The results of such combined computational and experimental screening approach led to the identification of a high-potency inhibitor.
authors.affiliation: Department of Biomolecular Sciences and Biotechnology, University of Milano, Milano, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Milani
authors.forename: Eloise
authors.initials: E
authors.lastname: Mastrangelo
authors.forename: Michela
authors.initials: M
authors.lastname: Bollati
authors.forename: Barbara
authors.initials: B
authors.lastname: Selisko
authors.forename: Etienne
authors.initials: E
authors.lastname: Decroly
authors.forename: Mickaël
authors.initials: M
authors.lastname: Bouvet
authors.forename: Bruno
authors.initials: B
authors.lastname: Canard
authors.forename: Martino
authors.initials: M
authors.lastname: Bolognesi
mesh_terms: D018360:Crystallography, X-Ray; D005416:Flavivirus / Q000737:chemistry*; D008780:Methyltransferases / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D008958:Models, Molecular; D011485:Protein Binding; D012315:RNA Caps / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism*; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry*
chemical_list: C096041:NS5 protein, flavivirus; D012315:RNA Caps; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; D008780:Methyltransferases