STRUCTURE DETERMINATION OF A VIRUS ENCODED CHAPERONIN

病毒编码伴侣蛋白的结构测定

• 批准号: 7956849
• 负责人: Ricardo A Bernal
• 金额: $ 1.41万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7956849
• 关键词: ATP Hydrolysis; ATP phosphohydrolase; Amino Acids; Bacteriophages; Base Pairing; Binding; Computer Retrieval of Information on Scientific Projects Database; Cryoelectron Microscopy; Crystallography; Data; Data Collection; Family; Funding; Genome; Grant; Home environment; Institution; Length; Maps; Molecular; Molecular Conformation; Myoviridae; Nucleotides; Open Reading Frames; Proteins; Research; Research Personnel; Resolution; Resources; Solutions; Source; Structure; United States National Institutes of Health; Virus; chaperonin; improved; member; protein folding; protein misfolding; structural biology; synchrotron radiation

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 EL, a member of the Myoviridae family of bacteriophages, is a massive phage whose genome is 211,215 base pairs in length and has 201 predicted open reading frames. This phage encodes its own chaperonin and is the first chaperonin ever found to be encoded by a virus. The function of a chaperonins in general is to assist in the proper folding of denatured or misfolded proteins. Chaperonins are also ATPases in that they hydrolyze ATP and use the resulting energy to aid in the protein folding. Chaperonins can have one of three different conformational states. The open form, with both ends open, a half-open form with one end open and a closed form with both ends closed off. Each of the conformational states is determined by the binding of ATP or ADP to the nucleotide binding pocket. There are also large conformational changes that occur upon binding of the substrate, which demonstrate that conformational changes occur not only upon binding and hydrolysis of ATP but upon binding of the substrate protein to be folded. Our lab has determined the structure of the EL virus chaperonin open conformation to 7 angstrom resolution by cryo-electron microscopy. The closed and half open conformations are currently at about 11 angstrom resolution each and are still improving with additional refinement cycles. We are now attempting to solve the structure to atomic resolution using x-ray crystallography. Preliminary data collection on our home source has produced diffraction to 4 angstrom resolution. We anticipate reaching better than 3 angstrom resolution using synchrotron radiation. Molecular replacement solutions have proven unsuccessful because know structures, namely bacterial GroEL, have an amino acid identity of less than 20%. Furthermore, the cryo-EM maps of the virus encoded chaperonin have shown tremendous differences in structure compared to bacterial GroEL. Collecting native and heavy atom data will therefore help us solve the structure to atomic resolution.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 噬菌体EL是噬菌体Myoviridae家族的成员，是一种巨大的噬菌体，其基因组长度为211，215个碱基对，具有201个预测的开放阅读框。 这种噬菌体编码自己的伴侣蛋白，是第一个发现的由病毒编码的伴侣蛋白。伴侣蛋白的功能通常是帮助变性或错误折叠的蛋白质正确折叠。伴侣蛋白也是ATP酶，因为它们水解ATP并使用产生的能量来帮助蛋白质折叠。伴侣蛋白可以具有三种不同构象状态之一。开放形式，两端开放，半开放形式，一端开放和封闭形式，两端封闭。每个构象状态由ATP或ADP与核苷酸结合口袋的结合决定。 也有大的构象变化，发生在结合的底物，这表明，构象变化不仅发生在结合和水解的ATP，但结合的底物蛋白质被折叠。 我们实验室已经确定了EL病毒伴侣蛋白开放构象的结构，以7埃分辨率的冷冻电子显微镜。封闭和半开放构象目前分别为约11埃分辨率，并且仍在通过额外的细化周期进行改进。我们现在正试图用X射线晶体学来解决原子分辨率的结构。初步数据收集我们的家庭来源产生衍射4埃分辨率。我们预期使用同步辐射达到优于3埃的分辨率。分子替代解决方案已被证明是不成功的，因为已知的结构，即细菌GroEL，具有小于20%的氨基酸同一性。此外，与细菌GroEL相比，病毒编码的伴侣蛋白的冷冻-EM图谱显示出结构上的巨大差异。因此，收集自然和重原子数据将有助于我们解决原子分辨率的结构。