HK97 BACTERIOPHAGE PROHEADS

HK97 噬菌体前体

• 批准号: 7725996
• 负责人: JOHN E JOHNSON
• 金额: $ 0.79万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7725996
• 关键词: Bacteriophages; Biological Models; Capsid; Capsid Proteins; Cleaved cell; Computer Retrieval of Information on Scientific Projects Database; Endopeptidases; Excision; Funding; Grant; Institution; Macromolecular Complexes; Molecular Conformation; Numbers; Peptide Hydrolases; Proteolysis; Research; Research Personnel; Resolution; Resources; Scaffolding Protein; Source; Structure; Surface; System; Tail; United States National Institutes of Health; Virus Assembly; X-Ray Crystallography; crosslink; macromolecular assembly; particle

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Bacteriophage HK97 is a lambda-like, tailed dsDNA bacteriophage that has emerged as a highly accessible model system for studies of particle assembly and maturation. This system allows a number of intermediate particle states to be isolated and characterized and hence provides excellent opportunities for detailed structural and biophysical analysis of complex macromolecular assembly. The HK97 prohead is composed of 420 copies of a 42kDa capsid protein that assemble into an T=7l icosahedral shell, called Prohead-I. Approximately 60 copies of the phage-encoded protease are packaged into the Prohead-I shell during assembly. After the capsid is formed, the protease cleaves off residues 2-103, called the ∆-domain, from the capsid proteins. The ∆-domain is a scaffolding protein and a crucial component for directing the capsid subunits to assemble into an icosahedral particle. After proteolysis, the resulting particle, called Prohead-II, resembles Prohead-I on the exterior, however the interior surface has been completely remodeled as a result of removal of the ∆-domains. Prohead-II enters the maturation cascade by capsid expansion and intersubunit crosslinking. In this proposal, we seek to determine a high resolution atomic structure of Prohead-I and Prohead-II by X-ray crystallography. The structure will allow us to compare subunit conformations and inter/intra capsomer interactions in the proheads with organizations previously observed in mature capsid states. A detailed structure will also help us to fully understand the determinants of virus assembly and the biophysical mechanism of capsid maturation.

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 噬菌体HK97是一种类似lambda的尾部dsDNA噬菌体，已经成为研究颗粒组装和成熟的一个高度可访问的模型系统。该系统允许分离和表征许多中间粒子状态，从而为复杂大分子组装的详细结构和生物物理分析提供了极好的机会。 HK97 Prohead由420个拷贝的42 kDa衣壳蛋白组成，组装成一个T=71的二十面体外壳，称为Prohead-I。在组装过程中，大约60个拷贝的噬菌体编码的蛋白酶被包装到Prohead-I壳中。在衣壳形成后，蛋白酶从衣壳蛋白中分解出残基2-103，称为-结构域。结构域是一种支架蛋白，也是引导衣壳亚单位组装成二十面体颗粒的关键成分。蛋白质分解后，生成的颗粒被称为Prohead-II，在外部类似于Prohead-I，但由于去除了-结构域，内部表面已完全重塑。Prohead-II通过衣壳扩张和亚基间交联进入成熟级联。 在这个方案中，我们试图通过X射线结晶学来确定Prohead-I和Prohead-II的高分辨率原子结构。该结构将使我们能够将探针中的亚基构象和包膜间/包膜内相互作用与以前在成熟衣壳状态下观察到的组织进行比较。一个详细的结构也将有助于我们充分了解病毒组装的决定因素和衣壳成熟的生物物理机制。