MYOFIBRILLAR, STRUCTURE IN STRIATED MUSCLE

昆虫飞行肌的肌原纤维结构是目前研究的热点 通过电子显微镜，X射线衍射， 定量显微镜和生化分析，并强调 肌球蛋白桥的结构和行为。 横桥是肌肉收缩的主要推动者， 大多数非肌肉运动，以及它们的高度有序的晶格 IFM中的安排允许平均方法提取 跨桥结构不同的状态，可以涉及到 它们棘轮式循环的不同阶段。 x射线和光学 衍射标准将指导我们寻找更好的固定， 单宁修饰戊二醛的肌动蛋白和交联桥 酸、二胺和聚乙二醇三嗪。 速冻 冷冻替代方法将被优化， 稳定状态的切片，如之前的僵硬和放松 尝试研究动态结构转换。 3-D 计算机重建从10-25纳米的部分，根据 多个倾斜视图和倾斜横截面，将 完成僵硬，并应用于一组necleotide诱导的 国家，以确定在大小，形状和 跨桥的域对齐。 计算机建模将 探索肌动蛋白的EM结构和僵硬的横桥如何能够 与X射线强度建模相一致。 电磁机械 单纤维的相关研究将表征两种新的 在乙二醇-AMPPNP-中遇到的交叉桥结构 诱导状态的进展，并将探索严谨的诱导， 张力检查的权力行程的长度，强度 桥梁连接和横桥“滑动”的影响。 我们 预计完成跨桥协调合作研究 通过EM/X射线和自旋标记进行定向，以及抗体 肌钙蛋白在横桥晶格内的定位。 中 不同的方法，定量显微镜（EM和 干扰）、Percoll中的浮力密度带和X射线 晶格间距的衍射测量将在 研究肌丝和原纤维的干质量含量， 制作昆虫和兔子的质量分布图 确定肌节交叉处的绝对蛋白质conon， 带，并解决灯丝之间的异常差异 质量和整个原纤维质量。

Myofibril structure of insect flight muscle (IFM) is being studied by coordinated use of electron microscopy, X-ray diffraction, quantitative microscopy and biochemical analysis, and emphasis on the structure and behavior of myosin crossbridges. Crossbridges are the primary movers in muscle contraction and most non-muscle motility, and their highly ordered lattice arrangement in IFM permits averaging methods to extract crossbridge structure indifferent states which can be related to different phases of their ratchet-like cycle. X-ray and optical diffraction criteria will guide our search for better fixation of actin and crossbridges by modifying glutaraldehyde with tannic acid, diamines, and polyethylene-glycol triazine. Quick-freeze and freeze-substitution methods will be optimized for thin- sectioning of stable states like rigor and relaxed before attempting the study of dynamic structural transitions. 3-D computer reconstructions from 10-25 nm sections, based on multiple tilt views and on oblique cross sections, will be completed for rigor and applied to a group of necleotide-induced states, to establish definitively the variation in size, shape and domain alignment of crossbridges. Computer modelling will explore how EM structure of actin and crossbridges of rigor can be reconciled with X-ray intensity modelling. EM-mechanical correlation studies of single fibers will characterize two new crossbridge configurations encountered in glycol-AMPPNP- induced progression of states, and will explore rigor induction and tension to examine the length of the power-stroke, strength of bridge attachment, and effects of crossbridge "slippage". We expect to finish coordinated collaborative studies of crossbridge orientation by EM/X-ray and spin-labelling, and antibody localization of troponin within the crossbridge lattice. IN a different approach, quantitative microscopy (EM and interference), buoyant density banding in Percoll, and X-ray diffraction measurement of lattice spacing will be coordinated in studies of dry mass content of myofilaments and fibrils, to produce mass distribution profiles of insect and rabbit sarcomeres, ascertain absolute protein conon in sarcomere cross- bands, and to resolve an anomalous discrepancy between filament mass and whole fibril mass.