| 1. |
- Högbom, Martin, et al.
(författare)
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The active form of the norovirus RNA-dependent RNA polymerase is a homodimer with cooperative activity
- 2009
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Ingår i: Journal of General Virology. - : Microbiology Society. - 0022-1317 .- 1465-2099. ; 90:Pt 2, s. 281-91
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Tidskriftsartikel (refereegranskat)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.
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| 2. |
- Rohayem, Jacques, et al.
(författare)
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Antiviral strategies to control calicivirus infections
- 2010
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Ingår i: Antiviral Research. - : Elsevier BV. - 0166-3542 .- 1872-9096. ; 87:2, s. 162-178
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Forskningsöversikt (refereegranskat)abstract
- Caliciviridae are human or non-human pathogenic viruses with a high diversity. Some members of the Caliciviridae, i.e. human pathogenic norovirus or rabbit hemorrhagic disease virus (RHDV), are worldwide emerging pathogens. The norovirus is the major cause of viral gastroenteritis worldwide, accounting for about 85% of the outbreaks in Europe between 1995 and 2000. In the United States, 25 million cases of infection are reported each year. Since its emergence in 1984 as an agent of fatal hemorrhagic diseases in rabbits, RHDV has killed millions of rabbits and has been dispersed to all of the inhabitable continents. In view of their successful and apparently increasing emergence, the development of antiviral strategies to control infections due to these viral pathogens has now become an important issue in medicine and veterinary medicine. Antiviral strategies have to be based on an understanding of the epidemiology, transmission, clinical symptoms, viral replication and immunity to infection resulting from infection by these viruses. Here, we provide an overview of the mechanisms underlying calicivirus infection, focusing on the molecular aspects of replication in the host cell. Recent experimental data generated through an international collaboration on structural biology, virology and drug design within the European consortium VIZIER is also presented. Based on this analysis, we propose antiviral strategies that may significantly impact on the epidemiological characteristics of these highly successful viral pathogens.
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| 3. |
- Speroni, Silvia, et al.
(författare)
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Structural and Biochemical Analysis of Human Pathogenic Astrovirus Serine Protease at 2.0 angstrom Resolution
- 2009
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Ingår i: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 387:5, s. 1137-1152
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Tidskriftsartikel (refereegranskat)abstract
- Astroviruses are single-stranded RNA viruses with a replication strategy based on the proteolytic processing of a polyprotein precursor and subsequent release of the viral enzymes of replication. So far, the catalytic properties of the astrovirus protease as well as its structure have remained uncharacterized. In this study, the three-dimensional crystal structure of the predicted protease of human pathogenic astrovirus has been solved to 2.0 angstrom resolution. The protein displays the typical properties of trypsin-like enzymes but also several characteristic features: (i) a catalytic Asp-His-Ser triad in which the aspartate side chain is oriented away from the histidine, being replaced by a water molecule; (ii) a non-common conformation and composition of the SI pocket; and (iii) the lack of the typical surface beta-ribbons together with a "featureless" shape of the substrate-binding site. Hydrolytic activity assays indicate that the S1 pocket recognises Glu and Asp side chains specifically, which, therefore, are predicted to occupy the P1 position on the substrate cleavage site. The positive electrostatic potential featured by the S1 region underlies this specificity. The comparative structural analysis highlights the peculiarity of the astrovirus protease, and differentiates it from the human and viral serine proteases. (C) 2009 Elsevier Ltd. All rights reserved.
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