ELECTRON CRYSTALLOGRAPHY OF ACROSOMAL BUNDLE

顶体束的电子晶体学

• 批准号: 7598578
• 负责人: MICHAEL F. SCHMID
• 金额: $ 9.77万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-12-01 至 2007-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7598578
• 关键词: Actins; Biological; Cell Nucleus; Computer Retrieval of Information on Scientific Projects Database; Decompression Sickness; Electrons; F-Actin; Fertilization; Filament; Fingers; Funding; Grant; Institution; Limulus; Membrane; Microfilaments; Motor; Process; Proteins; Research; Research Personnel; Resources; Rotation; Source; Standards of Weights and Measures; Structure; United States National Institutes of Health; base; crosslink; electron crystallography; polymerization; scruin; sperm cell

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. In the unactivated Limulus sperm, a 60 ¿m-long bundle of actin filaments crosslinked by scruin is bent and twisted into a coil around the base of the nucleus. At fertilization the bundle uncoils and fully extends in five seconds to support a finger of membrane, the acrosomal process. This biological spring is powered by stored elastic energy and does not require the action of motor proteins or actin polymerization. Our 9.5 ¿ electron cryomicroscopic structure of the extended bundle shows that twist, tilt, and rotation of actin-scruin subunits deviate widely from a "standard" F-actin filament. This deviation appears to be related to the packing requirements of the scruin cross-linkers. The structural organization allows filaments to pack into a highly ordered and rigid bundle in the extended state, but also suggests a mechanism for storing and releasing energy between the coiled and extended states. We are currently analyzing the structure and organization of the actin filament in the bundle, the structure of the scruin, its relationship to the actin, and its packing in the bundle.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目和 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 在未激活的鲎精子中，一束 60 米长的肌动蛋白丝通过细丝交联，弯曲并扭曲成围绕细胞核底部的线圈。受精时，束展开并在五秒钟内完全伸展以支撑膜指，即顶体过程。这种生物弹簧由储存的弹性能提供动力，不需要运动蛋白或肌动蛋白聚合的作用。我们的延伸束的 9.5° 电子冷冻显微镜结构表明，肌动蛋白-scruin 亚基的扭曲、倾斜和旋转与“标准”F-肌动蛋白丝有很大偏差。这种偏差似乎与检查交联剂的包装要求有关。这种结构组织允许细丝在伸展状态下堆积成高度有序且刚性的束，但也提出了一种在卷曲状态和伸展状态之间存储和释放能量的机制。 我们目前正在分析束中肌动蛋白丝的结构和组织、丝束的结构、其与肌动蛋白的关系以及其在束中的堆积。