Fan S F, Dewey M M, Colflesh D, Chu B
Department of Anatomical Sciences, State University of New York at Stony Brook 11794.
Biophys J. 1987 Nov;52(5):859-66. doi: 10.1016/S0006-3495(87)83279-4.
With the dynamic light scattering method, we have shown that calcium ions increase the high-frequency internal motions of isolated thick filaments of Limulus striated muscle in the presence of ATP (Kubota, K., B. Chu, Shih-fang Fan, M.M. Dewey, P. Brink, and D. Colflesh. J. Mol. Biol. 1983. 166:329 and Fan, S.-f., M.M. Dewey, D. Colflesh, B. Gaylinn, R. Greguski, and B. Chu. Biophys. J. 1985. 47:809). If ATP is removed from the suspending medium, an increase of high-frequency internal motions also has been observed with characteristics different from those of filaments suspended in a medium containing ATP and calcium ions. These internal motions appear whether calcium ions are present or not and are suppressed by trifluoperazine (TFP). The motions differ from the calcium ion-induced motions in that (a) an energy supply is not required; (b) they are insensitive to heat treatment (42 degrees C, 10 min) and (c) they are also insensitive to phenylmethylsulfonyl fluoride which blocks the motions in the presence of ATP and calcium ions (Fan, Shih-fang, M.M. Dewey, D. Colflesh, B. Gaylinn, R. Greguski, and B. Chu. 1985. Biochim. Biophys. Acta. 827:101). Electron micrographs of negatively stained thick filaments in an ATP-free medium show that the majority of crossbridges extend out from the backbone of the filament and optical diffraction patterns from these filaments lack layer lines arising from the crossbridges. The flexibility of the thick filaments suspended in ATP-free media increases.
运用动态光散射法，我们已经证明，在存在三磷酸腺苷（ATP）的情况下，钙离子会增加鲎横纹肌分离出的粗肌丝的高频内部运动（久保田，K.，B. 朱，范世芳，M.M. 杜威，P. 布林克，以及D. 科尔弗莱什。《分子生物学杂志》1983年。第166卷：第329页；以及范，S.-f.，M.M. 杜威，D. 科尔弗莱什，B. 盖林，R. 格雷古斯基，以及B. 朱。《生物物理学杂志》1985年。第47卷：第809页）。如果从悬浮介质中去除ATP，也观察到了高频内部运动的增加，其特征与悬浮在含有ATP和钙离子的介质中的肌丝不同。无论是否存在钙离子，这些内部运动都会出现，并且会被三氟拉嗪（TFP）抑制。这些运动与钙离子诱导的运动不同之处在于：（a）不需要能量供应；（b）它们对热处理（42摄氏度，10分钟）不敏感；（c）它们对苯甲基磺酰氟也不敏感，而苯甲基磺酰氟在存在ATP和钙离子的情况下会阻断运动（范，世芳，M.M. 杜威，D. 科尔弗莱什，B. 盖林，R. 格雷古斯基，以及B. 朱。1985年。《生物化学与生物物理学报》。第827卷：第101页）。在无ATP介质中对负染粗肌丝的电子显微镜照片显示，大多数横桥从肌丝主干伸出，并且这些肌丝的光学衍射图谱缺乏由横桥产生的层线。悬浮在无ATP介质中的粗肌丝的柔韧性增加。
