title: The active form of the norovirus RNA-dependent RNA polymerase is a homodimer with cooperative activity.
abstract: Norovirus (NV) is a leading cause of gastroenteritis worldwide and a major public health concern. So far, the replication strategy of NV remains poorly understood, mainly because of the lack of a cell system to cultivate the virus. In this study, the function and the structure of a key viral enzyme of replication, the RNA-dependent RNA polymerase (RdRp, NS7), was examined. The overall structure of the NV NS7 RdRp was determined by X-ray crystallography to a 2.3 A (0.23 nm) resolution (PDB ID 2B43), displaying a right-hand fold typical of the template-dependent polynucleotide polymerases. Biochemical analysis evidenced that NV NS7 RdRp is active as a homodimer, with an apparent K(d) of 0.649 microM and a positive cooperativity (Hill coefficient n(H)=1.86). Crystals of the NV NS7 homodimer displayed lattices containing dimeric arrangements with high shape complementarity statistics. This experimental data on the structure and function of the NV RdRp may set the cornerstone for the development of polymerase inhibitors to control the infection with NV, a medically relevant pathogen.
authors.affiliation: Stockholm Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Högbom
authors.affiliation: Institut für Virologie, The Calicilab, Medizinisch-Theoretisches Zentrum, Dresden, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Jäger
authors.affiliation: Institut für Virologie, The Calicilab, Medizinisch-Theoretisches Zentrum, Dresden, Germany.
authors.forename: Ivonne
authors.initials: I
authors.lastname: Robel
authors.affiliation: Institute of Cell and Molecular Biology, Uppsala University, Sweden.
authors.forename: Torsten
authors.initials: T
authors.lastname: Unge
authors.affiliation: Institut für Virologie, The Calicilab, Medizinisch-Theoretisches Zentrum, Dresden, Germany.
authors.forename: Jacques
authors.initials: J
authors.lastname: Rohayem
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray; D019281:Dimerization; D007700:Kinetics; D008958:Models, Molecular; D029322:Norovirus / Q000201:enzymology*; D011487:Protein Conformation; D012367:RNA, Viral / Q000737:chemistry / Q000378:metabolism; D012324:RNA-Dependent RNA Polymerase / Q000737:chemistry* / Q000378:metabolism*; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D012367:RNA, Viral; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase