title: Structural studies of the resistance of influenza virus neuramindase to inhibitors.
abstract: Zanamivir and oseltamivir, specific inhibitors of influenza virus neuraminidase, have significantly different characteristics in resistance studies. In both cases resistance is known to arise through mutations in either the hemagglutinin or neuraminidase surface proteins. A new inhibitor under development by Biocryst Pharmaceuticals, BCX-1812, has both a guanidino group, as in zanamivir, and a bulky hydrophobic group, as in oseltamivir. Using influenza A/NWS/Tern/Australia/G70C/75 (H1N9), neuraminidase variants E119G and R292K have previously been selected by different inhibitors. The sensitivity of these variants to BCX-1812 has now been measured and found in both cases to be intermediate between those of zanamivir and oseltamivir. In addition, the X-ray crystal structures of the complexes of BCX-1812 with the wild type and the two mutant neuraminidases were determined. The ligand is bound in an identical manner in each structure, with a rearrangement of the side chain of E276 from its ligand-free position. A structural explanation of the mechanism of resistance of BCX-1812, relative to zanamivir and oseltamivir in particular, is provided.
authors.affiliation: The Walter and Eliza Hall Institute of Medical Research, P.O. Royal Melbourne Hospital, Parkville, Victoria 3050, Australia. bsmith@wehi.edu.au
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Smith
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: McKimm-Breshkin
authors.forename: Mandy
authors.initials: M
authors.lastname: McDonald
authors.forename: Ross T
authors.initials: RT
authors.lastname: Fernley
authors.forename: Joseph N
authors.initials: JN
authors.lastname: Varghese
authors.forename: Peter M
authors.initials: PM
authors.lastname: Colman
mesh_terms: D000081:Acetamides / Q000737:chemistry / Q000494:pharmacology; D000146:Acids, Carbocyclic; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology*; D018360:Crystallography, X-Ray; D003517:Cyclopentanes / Q000737:chemistry / Q000494:pharmacology*; D024882:Drug Resistance, Viral; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D006146:Guanidines; D029521:Alphainfluenzavirus / Q000187:drug effects* / Q000201:enzymology; D008958:Models, Molecular; D009154:Mutation; D009439:Neuraminidase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics; D053139:Oseltamivir; D011485:Protein Binding; D011714:Pyrans; D012794:Sialic Acids / Q000737:chemistry / Q000494:pharmacology; D053243:Zanamivir
chemical_list: D000081:Acetamides; D000146:Acids, Carbocyclic; D000998:Antiviral Agents; D003517:Cyclopentanes; D004791:Enzyme Inhibitors; D006146:Guanidines; D011714:Pyrans; D012794:Sialic Acids; D053139:Oseltamivir; D009439:Neuraminidase; D053243:Zanamivir; C414210:peramivir