STRUCTURAL BIOLOGY OF MACROMOLECULAR STRUCTURE

大分子结构的结构生物学

• 批准号: 5200619
• 负责人: A C STEVEN
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ARTHRITIS AND MUSCULOSKELETAL AND SKIN DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/5200619
• 关键词: Baculoviridae; bacterial virus; bovine papillomavirus; capsid; conformation; crosslink; cryoscience; herpes simplex virus 1; image processing; macromolecule; protein biosynthesis; protein folding; protein structure function; proteolysis; scanning transmission electron microscopy; structural biology; virus protein

This Laboratory seeks to elucidate the mechanisms that control the assembly of macromolecular complexes, with particular emphasis on their functional rationale. Over the past year, a major effort has been directed towards enhancing the resolution of three-dimensional density maps of icosahedral virus capsids calculated from cryo-electron micrographs. Thus, we have characterized the events whereby limited proteolysis of the major capsid protein of bacteriophage HK97 induces the stabilizing expansion of the capsid. The excised domain resides on the inner surface of the hexons and pentons, and its removal permits the prohead to maturation transformation to proceed. This transition facilitates the formation of covalent cross-links between neighboring subunits. (ii) In bovine papillomavirus, the analysis has been extended to a resolution of better than 1nm, revealing a wealth of detail concerning the structures of the pentameric capsomers, and disclosing the possible location of the minor capsid protein, L2. (iii) Capsids of herpes simplex virus assembled from proteins synthesized in insect cells from baculovirus expression vectors have been found to be structurally authentic. The 12kDa VP26 protein has been shown to bind to the major capsid protein VP5 only in its hexon state, not in its penton state. From image analysis of negatively stained specimens of the ClpAP energy-dependent protease, the oligomeric natures of the subcomplexes have been defined, as has their mode of interaction. ClpP, the protease, consists of two 7-fold rings, and ClpA, the ATP-hydrolyzing component, forms hexameric rings. In active complexes, they stack axially, resulting in a symmetry mismatch that may have connotations of mutual rotational movement. Progress has also been made on the assembly of cornified cell envelopes of terminally differentiated keratinocytes, and on the domainal organization of bacteriophage tail-fiber proteins.

本实验室旨在阐明控制 大分子复合物的组装，特别强调其 功能原理。在过去一年中， 旨在提高三维密度的分辨率 由冷冻电子计算的二十面体病毒衣壳图 显微照片 因此，我们已经描述了有限的事件， 噬菌体HK 97主要衣壳蛋白的蛋白质水解诱导 稳定衣壳的扩张。切除的结构域位于 六子和五子的内表面，其去除允许 向成熟转化的过程。这一过渡 促进相邻的聚合物之间共价交联的形成 亚单位。(ii)在牛乳头瘤病毒中，分析已经扩展到 分辨率超过1纳米，显示出丰富的细节 关于五聚体壳粒的结构，并公开了 次要衣壳蛋白L2的可能位置。(iii)衣壳 由昆虫细胞中合成的蛋白质组装而成的单纯疱疹病毒 已经发现从杆状病毒表达载体的结构上 正宗的.已显示12kDa VP26蛋白结合主要的 衣壳蛋白VP5仅处于其六邻体状态，而不是处于其五邻体状态。 根据ClpAP阴性染色标本的图像分析， 能量依赖性蛋白酶，亚复合物的低聚性质 已经被定义，就像他们的互动模式一样。ClpP蛋白酶 由两个7重环和ClpA组成，ClpA是ATP水解组分， 形成六聚环。在活性复合物中，它们轴向堆叠， 在可能具有相互旋转含义的对称性失配中， 运动在细胞组装方面也取得了进展 终末分化的角质形成细胞的包膜，以及 噬菌体尾纤维蛋白的组织。