Urakova Nadya, Warden Andrew C, White Peter A, Strive Tanja, Frese Michael
Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT 2601, Australia.
Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, ACT 2601, Australia.
Viruses. 2017 Aug 1;9(8):202. doi: 10.3390/v9080202.
(RHDV) is a calicivirus that infects and frequently kills rabbits. Previously, we showed that the RHDV RNA-dependent RNA polymerase (RdRp) is associated with distinct, but yet uncharacterised subcellular structures and is capable of inducing a redistribution of Golgi membranes. In this study, we identified a partially hidden hydrophobic motif that determines the subcellular localisation of recombinant RHDV RdRp in transfected cells. This novel motif, LLWGCDVGVAVCAAAVFHNICY, is located within the F homomorph, between the conserved F3 and A motifs of the core RdRp domain. Amino acid substitutions that decrease the hydrophobicity of this motif reduced the ability of the protein to accumulate in multiple subcellular foci and to induce a rearrangement of the Golgi network. Furthermore, preliminary molecular dynamics simulations suggest that the RHDV RdRp could align with the negatively charged surfaces of biological membranes and undergo a conformational change involving the F homomorph. These changes would expose the newly identified hydrophobic motif so it could immerse itself into the outer leaflet of intracellular membranes.
兔出血症病毒（RHDV）是一种感染兔子并常致其死亡的杯状病毒。此前，我们发现RHDV的RNA依赖RNA聚合酶（RdRp）与不同但尚未明确的亚细胞结构相关联，并且能够诱导高尔基体膜的重新分布。在本研究中，我们鉴定出一个部分隐藏的疏水基序，该基序决定了重组RHDV RdRp在转染细胞中的亚细胞定位。这个新的基序LLWGCDVGVAVCAAAVFHNICY位于F同形体中，在核心RdRp结构域的保守F3和A基序之间。降低该基序疏水性的氨基酸替换降低了蛋白质在多个亚细胞灶中积累以及诱导高尔基体网络重排的能力。此外，初步的分子动力学模拟表明，RHDV RdRp可以与生物膜的带负电表面对齐，并经历涉及F同形体的构象变化。这些变化将暴露新鉴定的疏水基序，使其能够浸入细胞内膜的外小叶中。
