MACROMOLECULAR STRUCTURE

大分子结构

• 批准号: 4689563
• 负责人: A C STEVEN
• 金额: --
• 依托单位: NAT INST OF ARTHRITIS, DIABETES, DIGESTIVE & KIDNEY 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/4689563
• 关键词: Vesiculovirus; bacteriophage T4; calorimetry; chemical structure; chromatography; electron microscopy; human tissue; image processing; macromolecule; molecular biology; nucleocapsid; scanning electron microscopy; tobacco mosaic virus; virus RNA; virus envelope; virus morphology

Virus Structures have been analyzed in the caes of (i) Herpes Simplex Virus where we have shown by computer image processing of electron micrographs that the major capsomer of the icosahedral capsid is a hexamer of a 155kDa protein, in the form of a cylinder 14nm in length, with a central channel that is about 4nm at the outer surface but much narrower on the inner surface. (ii) The tail fibers of bacteriophage T7 have been analyzed at high resolution by correlating secondary structure predictions of the 60kDa gp17 polypeptide with computer-processed electron images of individual fibers. Each fiber is an oligomer (probably a dimer) of parallel chains that are composed of three domains. The amino-terminal domains link the fibers to the tail; the central domains form a coiled-coil Alpha-helical rope to make up the proximal half-fiber, 19nm in length; the carboxy-terminal domains form inter-chain crossed Beta-sheets which form a linear sequence of four nodules in the distal half-fiber, also 19nm long. In addition we have determined the helical structures of the bacterial fimbriae of sertotypes #2 and #6 from, Bordetella pertussis, using paracrystals of purified fimbriae. In both cases, the fimbria is a single-start helix which contains five copies of the fimbrial portein (22kDa) in two helical turns, corresponding to an axial shift of 13nm. The outer diameter of the fimbria is about 6nm. Radial density mapping of intermediate filaments of vimentin and of epidermal keratin shows them both to have backbones of uniform average desneity with a diameter of 9-10nm surrounded by a shell of relatively diffuse perpheral density extending to an outer diameter of approximately 15nm. The backbone appears to be made up of a helical packing of the conservative Alph-helical rod-domains of the IF subunits (311 amino acids) whereas the peripheral density is contributed by the highly variable non-Alpha-helical end-domains which contain one third of the total mass. This model holds that the end-domain confer the individual functional specificities of different types of intermediate filaments.

对单纯疱疹病毒(HSV)的病毒结构进行了分析 我们已经通过电子显微照片的计算机图像处理展示了 二十面体衣壳的主要衣壳是一个155 kDa的六角体 蛋白质，呈14 nm长的圆柱体，具有中央通道 这在外表面大约是4纳米，但在内部要窄得多 浮出水面。(Ii)噬菌体T7的尾部纤维已在 关联60 kDa二级结构预测的高分辨率 带有计算机处理的个体电子图像的gp17多肽 纤维。每根纤维都是平行链的低聚物(可能是二聚体) 它们由三个域组成。氨基末端结构域连接 纤维到尾巴；中心区域形成一个盘绕的螺旋阿尔法螺旋 用于组成近端半纤维的绳索，长度为19 nm； 羧基末端结构域形成链间交叉的Beta-Sheet，形成 远端半纤维由四个结节组成的线状序列，也有19 nm长。 此外，我们还测定了细菌的螺旋结构 百日咳杆菌2号和6号血清型菌毛的研究 纯化的菌毛的准晶。在这两种情况下，菌毛都是一个 含有5个拷贝的菌毛蛋白的单起始螺旋 (22 KDa)在两个螺旋转弯中，对应于13 nm的轴向移动。这个 菌毛的外径约为6 nm。的径向密度贴图 波形蛋白和表皮角蛋白的中间丝都显示了它们。 具有平均密度均匀、直径9-10纳米的骨干 由外围密度相对分散的外壳包围，延伸到 外径约为15纳米。脊椎似乎是由 的保守Alph-螺旋杆域的螺旋堆积 IF亚基(311个氨基酸)，而外周密度贡献 由含有一个的高度可变的非α螺旋末端结构域 占总质量的三分之一。该模型认为，端域赋予 不同类型中间体的个体功能特性 细丝。