ELECTRON CRYSTALLOGRAPHY OF ACROSOMAL BUNDLE

顶体束的电子晶体学

• 批准号: 7357770
• 负责人: MICHAEL F. SCHMID
• 金额: $ 9.04万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-12-01 至 2006-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7357770
• 关键词: ELECTRON; CRYSTALLOGRAPHY; ACROSOMAL; BUNDLE

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NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子弹和调查员（PI）可能已经从其他NIH来源获得了主要资金，因此可以在其他清晰的条目中代表。列出的机构是针对该中心的，这不是调查人员的机构。在未激活的利卢卢斯精子中，由Scruin交叉链接的60束肌动蛋白丝弯曲并扭曲成核底部周围的线圈。在受精时，束脱落并在五秒钟内完全延伸，以支撑膜的手指，即粘体过程。该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9.5€延长束的电子冷冻显微镜结构表明，肌动蛋白 - cruin亚基的扭曲，倾斜和旋转偏离了“标准” F-肌动蛋白细丝。此离开似乎与Scruin交联的填料要求有关。结构组织允许细丝在扩展状态下包装成一个高度有序且刚性的束，但也提出了一种机制，可以在盘绕状态和扩展状态之间存储和释放能量。我们目前正在分析束中肌动蛋白细丝的结构和组织，scruin的结构，其与肌动蛋白的关系以及其在捆绑包中的包装。