乙型肝炎病毒核心蛋白衣壳的组装通过存在和不存在RNA的高

StephenW

Assembly of Capsids from Hepatitis B Virus Core Protein Progresses through Highly Populated Intermediates in Presence and Absence of RNA
Ryan C Oliver, Wojciech Potrzebowski, Seyed Morteza Najibi, Martin Nors Pedersen, Lise Arleth, Najet Mahmoudi, Ingemar André

    PMID: 32672447 DOI: 10.1021/acsnano.0c03569

Abstract

The genetic material of viruses is protected by protein shells that are assembled from a large number of subunits in a process that is efficient and robust. Many of the mechanistic details underpinning efficient assembly of virus capsids are still unknown. The assembly mechanism of Hepatitis B capsids has been intensively researched using truncated core protein lacking the C-terminal domain responsible for binding genomic RNA. To resolve the assembly intermediates of hepatitis B virus (HBV), we studied the formation of nucleocapsids and empty capsids from full-length hepatitis B core proteins, using time-resolved small angle X-ray scattering. We developed a detailed structural model of the HBV capsid assembly process using a combination of analysis with multivariate curve resolution, structural modeling and Bayesian ensemble inference. The detailed structural analysis supports an assembly pathway that proceeds through the formation of two highly populated intermediates, a trimer of dimers and a partially closed shell consisting of around 40 dimers. These intermediates are on-path, transient, and efficiently convert into fully formed capsids. In the presence of an RNA oligo that binds specifically to the C-terminal domain the assembly proceeds via a similar mechanism as in the absence of nucleic acids. Comparisons between truncated and full-length HBV capsid proteins reveal that the unstructured C-terminal domain has a significant impact on the assembly process, and is required to obtain a more complete mechanistic understanding of HBV capsid formation. These results also illustrate how combining scattering information from different time-points during time-resolved experiments can be utilized to derive a structural model of protein self-assembly pathways.

StephenW

乙型肝炎病毒核心蛋白衣壳的组装通过存在和不存在RNA的高填充中间体进行
Ryan C Oliver，Wojciech Potrzebowski，Seyed Morteza Najibi，Martin Nors Pedersen，Lise Arleth，Najet Mahmoudi，IngemarAndré

    PMID：32672447 DOI：10.1021 / acsnano.0c03569

抽象

病毒的遗传物质受到蛋白质外壳的保护，该外壳由大量亚基组成，且组装过程高效而稳定。支持病毒衣壳有效组装的许多机制细节仍然未知。已经使用缺少负责结合基因组RNA的C末端结构域的截短的核心蛋白深入研究了乙型肝炎衣壳的组装机制。为了解决乙型肝炎病毒（HBV）的组装中间体，我们使用时间分辨的小角度X射线散射研究了全长乙型肝炎核心蛋白的核衣壳和空衣壳的形成。我们结合了多变量曲线解析度分析，结构建模和贝叶斯集成推理，开发了HBV衣壳装配过程的详细结构模型。详细的结构分析为组装路径提供了支持，该路径通过形成两个人口稠密的中间体，一个二聚体的三聚体和一个由约40个二聚体组成的部分封闭的壳进行。这些中间体是在途的，瞬态的，并有效地转化为完全形成的衣壳。在存在与C末端结构域特异性结合的RNA寡核苷酸的情况下，组装过程通过与不存在核酸时类似的机制进行。截短的和全长的HBV衣壳蛋白之间的比较表明，非结构化的C末端结构域对组装过程具有重大影响，并且需要获得对HBV衣壳形成的更完整的机理的理解。这些结果也说明了如何在时间分辨的实验过程中结合来自不同时间点的散射信息，以得出蛋白质自组装途径的结构模型。