Maéda Y, Boulin C, Gabriel A, Sumner I, Koch M H
Biophys J. 1986 Dec;50(6):1035-42. doi: 10.1016/S0006-3495(86)83547-0.
Small angle x-ray diffraction patterns were recorded from isometrically contracting Limulus (horseshoe crab) telson levator muscle using a multiwire proportional-area detector on the storage ring DORIS. In the pattern a substantial increase in intensity is observed on the thin-filament-associated layer-line at 1/38 nm-1 (the first actin layer-line) with a maximum increase at a radial spacing of R = 0.07 nm-1 but there is a much smaller change in the intensity of the 5.9-nm layer-line, which also arises from the thin filament structure. The results suggest that during contraction the myosin heads, presumably being attached to the thin filaments, are arranged along the long-stranded helical tracks of the thin filaments but that the spatial relationship between the heads and the actin monomers varies. Intensity increases have also been observed (Maéda et al., manuscript in preparation) in the part of the patterns from frog muscle and barnacle muscle, which are attributable to the first actin layer-line. It is thus likely that the intensity increase of the first actin layer-line on the Limulus pattern is associated not with structural features which are special to Limulus muscle, but with the tension generating processes that are shared by muscles in general.
使用多丝正比面积探测器在储存环DORIS上记录等长收缩的鲎尾节提肌的小角X射线衍射图谱。在图谱中，在1/38 nm-1处与细肌丝相关的层线（第一条肌动蛋白层线）强度大幅增加，在径向间距R = 0.07 nm-1处增加最大，但5.9 nm层线的强度变化小得多，该层线也源自细肌丝结构。结果表明，在收缩过程中，推测附着在细肌丝上的肌球蛋白头部沿细肌丝的长链螺旋轨道排列，但头部与肌动蛋白单体之间的空间关系有所不同。在青蛙肌肉和藤壶肌肉图谱的部分区域也观察到强度增加（前田等人，正在准备的手稿），这可归因于第一条肌动蛋白层线。因此，鲎图谱上第一条肌动蛋白层线的强度增加可能与鲎肌肉特有的结构特征无关，而是与一般肌肉共有的张力产生过程有关。
