Hwang Hyo-Jeong, Min Hye Jung, Yun Hyosuk, Pelton Jeffery G, Wemmer David E, Cho Kyoung-Oh, Kim Jeong-Sun, Lee Chul Won
Department of Chemistry, Chonnam National University, Gwangju 500-757, Republic of Korea.
Division of Physical Biosciences of Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA.
Biochem Biophys Res Commun. 2015 Apr 17;459(4):610-6. doi: 10.1016/j.bbrc.2015.02.156. Epub 2015 Mar 6.
Viral protein genome-linked (VPg) proteins play a critical role in the life cycle of vertebrate and plant positive-sense RNA viruses by acting as a protein primer for genome replication and as a protein cap for translation initiation. Here we report the solution structure of the porcine sapovirus VPg core (VPg(C)) determined by multi-dimensional NMR spectroscopy. The structure of VPg(C) is composed of three α-helices stabilized by several conserved hydrophobic residues that form a helical bundle core similar to that of feline calicivirus VPg. The putative nucleotide acceptor Tyr956 within the first helix of the core is completely exposed to solvent accessible surface to facilitate nucleotidylation by viral RNA polymerase. Comparison of VPg structures suggests that the surface for nucleotidylation site is highly conserved among the Caliciviridae family, whereas the backbone core structures are different. These structural features suggest that caliciviruses share common mechanisms of VPg-dependent viral replication and translation.
病毒蛋白基因组连接（VPg）蛋白在脊椎动物和植物正链RNA病毒的生命周期中发挥着关键作用，它作为基因组复制的蛋白引物以及翻译起始的蛋白帽。在此，我们报道了通过多维核磁共振光谱法测定的猪札幌病毒VPg核心（VPg(C)）的溶液结构。VPg(C)的结构由三个α螺旋组成，这些螺旋由几个保守的疏水残基稳定，形成了一个类似于猫杯状病毒VPg的螺旋束核心。核心第一个螺旋内推定的核苷酸受体Tyr956完全暴露于溶剂可及表面，以促进病毒RNA聚合酶进行核苷酸化。VPg结构的比较表明，核苷酸化位点的表面在杯状病毒科中高度保守，而主链核心结构则不同。这些结构特征表明，杯状病毒具有依赖VPg的病毒复制和翻译的共同机制。
