Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX, USA.
Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX, USA.
Virology. 2020 May;544:31-41. doi: 10.1016/j.virol.2020.02.006. Epub 2020 Feb 24.
Alphavirus genome replication is carried out by the viral replication complex inside modified membrane structures called spherules. The viral nonstructural protein 1 (nsP1) is the only membrane-associated protein that anchors the replication complex to the cellular membranes. Although an internal amphipathic helix of nsP1 is critical for membrane association, the mechanism of nsP1 interaction with membranes and subsequent membrane reorganization is not well understood. We studied the membrane interaction of chikungunya virus (CHIKV) nsP1 and show that both the CHIKV nsP1 protein and the amphipathic peptide specifically bind to negatively charged phospholipid vesicles. Using cryo-electron microscopy, we further show that nsP1 forms a contiguous coat on lipid vesicles and induces structural reorganization, while the amphipathic peptide alone failed to deform the membrane bilayer. This suggests that although amphipathic helix of nsP1 is required for initial membrane binding, the remaining cytoplasmic domain of nsP1 is involved in the subsequent membrane reorganization.
甲病毒基因组的复制是在经过修饰的膜结构（称为球体）内由病毒复制复合物完成的。病毒非结构蛋白 1（nsP1）是唯一与膜结合的蛋白，将复制复合物锚定在细胞膜上。尽管 nsP1 的内部两亲性螺旋对于膜结合至关重要，但 nsP1 与膜相互作用以及随后的膜重排的机制尚不清楚。我们研究了基孔肯雅病毒（CHIKV）nsP1 的膜相互作用，并表明 CHIKV nsP1 蛋白和两亲肽都特异性地与带负电荷的磷脂囊泡结合。使用冷冻电子显微镜，我们进一步表明 nsP1 在脂质囊泡上形成连续的外壳并诱导结构重排，而单独的两亲肽则无法使膜双层变形。这表明，尽管 nsP1 的两亲性螺旋对于初始膜结合是必需的，但 nsP1 的剩余细胞质结构域参与了随后的膜重排。
