ELECTRON CRYSTALLOGRAPHY OF ACROSOMAL BUNDLE

顶体束的电子晶体学

• 批准号: 8168524
• 负责人: PAUL T. MATSUDAIRA
• 金额: $ 2.15万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-15 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8168524
• 关键词: Actins; Biological; Cell Nucleus; Computer Retrieval of Information on Scientific Projects Database; Electrons; F-Actin; Fertilization; Filament; Fingers; Funding; Grant; Institution; Limulus; Membrane; Microfilaments; Motor; Process; Proteins; Research; Research Personnel; Resources; Rotation; Source; 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.

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。 在未激活的蛙类精子中，一束60米长的肌动蛋白细丝由细菌素交织在一起，弯曲并缠绕在细胞核的底部。在受精时，顶体束在5秒内解开并完全伸展，以支撑一根指状膜，即顶体突起。这种生物弹簧由储存的弹性能量提供动力，不需要马达蛋白或肌动蛋白聚合的作用。我们的9.5°电子冷冻显微镜结构表明，肌动蛋白-肌动蛋白亚基的扭曲、倾斜和旋转与“标准”的F-肌动蛋白细丝有很大的偏离。这种偏差似乎与丁香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的刚性束，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细丝的结构和组织，肌动蛋白的结构，它与肌动蛋白的关系，以及它在束中的堆积。