Structural biology of the hepatitis B virus: from assembly towards design of therapeutics

尽管有疫苗可供使用，但世界上三分之一的人口在其一生中感染了B型肝炎，超过2.4亿人已发展为慢性感染，使他们处于发展肝细胞癌、肝硬化和肝功能衰竭的高风险之中。现有药物无法清除病毒，逃逸突变对疫苗接种构成挑战。多样化的抗病毒策略是期望的，其靶向病毒进入和复制，特别是衣壳组装和复制，以及维持病毒的宿主细胞因子。合理设计治疗方法的先决条件是所有病毒组分的详细结构框架。尽管广泛表征的肝炎B病毒粒子，没有统一的概念存在如何包膜，衣壳和基因组相互作用和组装，以产生功能性病毒颗粒在原子尺度。 这种病毒的结构生物学的一个障碍是其内在的异质性，瞬时相互作用和动力学，这是潜在的相关功能。我们将采用核磁共振技术联合在解决方案和固定状态，以监测包膜和衣壳蛋白，核酸和药物分子，定位相互作用的网站，并建立这种相互作用如何触发整个病毒体的结构和动力学变化。特别是，我们的主要研究兴趣将是合理化的包膜蛋白的结构组织和他们的附件的衣壳，以确定主要的表面表位的结构-的基础上的乙型肝炎B疫苗-和表征的构象和空间动态的灵活的部分，以及包装的病毒基因组内的衣壳。该项目的长期目标是在病毒生命周期的所有阶段推导出完整病毒体的结构模型，将晶体学和冷冻电子显微镜的数据与磁共振动力学和相互作用的洞察力结合起来。这样的模型不仅可以使病毒粒子成熟合理化，而且可以预测干扰装配和破坏信号网络的潜在干预措施，这将使干扰病毒生命周期的分子的合理设计成为可能，用于B型肝炎的预防和治疗。我们将与病毒学家和研究医学科学家合作，以最大限度地发挥该项目的转化影响。

Despite the availability of a vaccine, a third of the world population has been infected with hepatitis B during their lifetime and more than 240 million people have developed a chronic infection, leaving them at high risk of developing hepatocellular carcinoma, cirrhosis and liver failure. Available drugs cannot clear the virus and escape mutations pose challenges to vaccination. A diversification of antiviral strategies is desirable targeting both virus entry and replication, in particular capsid assembly and envelopment, as well as host cell factors that sustain the virus. A prerequisite for the rational design of therapeutics is a detailed structural framework of all viral components. Despite extensive characterization of the hepatitis B virion, no unifying concept exists how the envelope, the capsid and the genome interact and assemble to yield functional viral particles at the atomic scale. One obstacle in the structural biology of this virus is its intrinsic heterogeneity, transient interactions, and dynamics, which are potentially relevant for function. We will employ nuclear magnetic resonance techniques jointly in solution and the immobilized state to monitor envelope and capsid proteins, nucleic acids and drug molecules, localizing sites of interaction and establishing how such interactions trigger structural and dynamical changes throughout the virions. In particular, our key research interests will be to rationalize the structural organization of the envelope proteins and their attachment to the capsid, to determine the structure of major surface epitope – the basis of the Hepatitis B vaccine – and to characterize the conformational and spatial dynamics of flexible segments as well as the packaging of the viral genome within the capsid. The long-term goal of this project will be to derive a structural model of the complete virion during all stages of the viral life cycle, uniting data from crystallography and cryo electron microscopy with insight into dynamics and interactions from magnetic resonance. Such a model will not only allow to rationalize virion maturation but also to predict potential interventions disturbing assembly and breaking signaling networks, which will enable the rational design of molecules that interfere with the viral life cycle for hepatitis B prevention and therapy. We will collaborate with virologists and researching medical scientists in order to maximize the translational impact of the project.