乙型肝炎病毒核心蛋白突变体的装配特性与它们对装配指导

StephenW

Assembly Properties of Hepatitis B Virus Core Protein Mutants Correlate with Their Resistance to Assembly-Directed Antivirals
Lu Ruan, Jodi A. Hadden, Adam Zlotnick
J.-H. James Ou, Editor
DOI: 10.1128/JVI.01082-18

    ArticleFigures & DataInfo & Metrics
    PDF

ABSTRACT

The hepatitis B virus (HBV) capsid or core protein (Cp) can self-assemble to form an icosahedral capsid. It is now being pursued as a target for small-molecule antivirals that enhance the rate and extent of its assembly to yield empty and/or aberrant capsids. These small molecules are thus called core protein allosteric modulators (CpAMs). We sought to understand the physical basis of CpAM-resistant mutants and how CpAMs might overcome them. We examined the effects of two closely related CpAMs, HAP12 and HAP13, which differ by a single atom but have drastically different antiviral activities, on the assembly of wild-type Cp and three T109 mutants (T109M, T109I, and T109S) that display a range of resistances. The T109 side chain forms part of the mouth of the CpAM binding pocket. A T109 mutant that has substantial resistance even to a highly active CpAM strongly promotes normal assembly. Conversely, a mutant that weakens assembly is more susceptible to CpAMs. In crystal and cryo-electron microscopy (cryo-EM) structures of T=4 capsids with bound CpAMs, the CpAMs preferentially fit into two of four quasi-equivalent sites. In these static representations of capsid structures, T109 does not interact with the neighboring subunit. However, all-atom molecular dynamics simulations of an intact capsid show that T109 of one of the four classes of CpAM site has a hydrophobic contact with the neighboring subunit at least 40% of the time, providing a physical explanation for the mutation's ability to affect capsid stability, assembly, and sensitivity to CpAMs.

IMPORTANCE The HBV core protein and its assembly into capsids have become important targets for development of core protein allosteric modulators (CpAMs) as antivirals. Naturally occurring T109 mutants have been shown to be resistant to some of these CpAMs. We found that mutation of T109 led to changes in capsid stability and recapitulated resistance to a weak CpAM, but much less so than to a strong CpAM. Examination of HBV capsid structures, determined by cryo-EM and crystallography, could not explain how T109 mutations change capsid stability and resistance. However, by mining data from a microsecond-long all-atom molecular dynamics simulation, we found that the capsid was extraordinarily flexible and that T109 can impede entry to the CpAM binding site. In short, HBV capsids are incredibly dynamic and molecular mobility must be considered in discussions of antiviral mechanisms.

StephenW

乙型肝炎病毒核心蛋白突变体的装配特性与它们对装配指导的抗病毒药物的抗性相关
陆阮，Jodi A. Hadden，Adam Zlotnick
J.-H. James Ou，编辑
DOI：10.1128 / JVI.01082-1​​8

    ArticleFigures＆DataInfo＆Metrics
    PDF

抽象

乙型肝炎病毒（HBV）衣壳或核心蛋白（Cp）可以自组装形成二十面体衣壳。现在正在寻求作为小分子抗病毒药物的靶标，其增强其组装的速率和程度以产生空的和/或异常的衣壳。因此，这些小分子被称为核心蛋白质变构调节剂（CpAM）。我们试图了解CpAM抗性突变体的物理基础以及CpAM如何克服它们。我们检测了两种密切相关的CpAMs，HAP12和HAP13的影响，它们在一个原子上有所不同，但抗病毒活性却大不相同，对野生型Cp和三个T109突变体（T109M，T109I和T109S）的组装显示了阻力范围。 T109侧链形成CpAM结合口袋的一部分。即使对高活性CpAM具有显着抗性的T109突变体也强烈促进正常组装。相反，削弱组装的突变体更容易受到CpAM的影响。在具有结合的CpAM的T = 4衣壳的晶体和低温电子显微镜（cryo-EM）结构中，CpAM优先适合四个准等效位点中的两个。在衣壳结构的这些静态表示中，T109不与相邻亚基相互作用。然而，完整衣壳的全原子分子动力学模拟显示四种CpAM位点之一的T109至少有40％的时间与相邻亚基疏水接触，为突变的影响能力提供了物理解释。衣壳稳定性，装配和对CpAM的敏感性。

重要性HBV核心蛋白及其组装成衣壳已成为核心蛋白质变构调节剂（CpAMs）作为抗病毒药物开发的重要目标。已显示天然存在的T109突变体对这些CpAM中的一些具有抗性。我们发现T109的突变导致衣壳稳定性的改变和对弱CpAM的重现性抵抗，但远低于强CpAM。通过冷冻EM和晶体学确定的HBV衣壳结构的检查不能解释T109突变如何改变衣壳稳定性和抗性。然而，通过从微秒长的全原子分子动力学模拟中挖掘数据，我们发现衣壳非常灵活，T109可以阻止进入CpAM结合位点。简而言之，HBV衣壳具有令人难以置信的动态，在讨论抗病毒机制时必须考虑分子流动性。

newchinabok

StephenW 发表于 2018-9-27 12:28
乙型肝炎病毒核心蛋白突变体的装配特性与它们对装配指导的抗病毒药物的抗性相关
陆阮，Jodi A. Hadden，Ada ...

以前看过这篇文章，核衣壳也有抗药性