Lednev V V, Srebnitskaia L K, Kornev A N, Malinchik S B
Biofizika. 1982 May-Jun;27(3):493-7.
Frog sartorius muscles were skinned with the help of detergent Triton X-100 in relaxing solution and then rigorized in the solution free of ATP and calcium (Ca2+-free rigor). Some of the X-ray diffraction patterns obtained from such muscles differed drastically from the patterns of usual "calcium" rigor state of the muscle. Analysis of the X-ray diffraction patterns of Ca2+-free rigor state of the muscle allows the following conclusions to be made. (1) It is proved that the so-called forbidden meridional reflections localised in groups at the successive orders of the repeat period of about 430 A are due to diffraction on the lattice formed by minor proteins of the thick filaments. This must be taken into account while interpreting the intensity changes of the meridional 143 and 215 A reflections in the contracting muscle. (2) The shafts of the myosin-containing filaments may exist in two different structural states; the transition between these states takes place on the change of calcium concentration. (3) The deflection of myosin cross-bridges from the shafts of the filaments is possible at either of two conformations of the myosin shafts. (4) The formation of actomyosin rigor-complexes does not necessarily leads to a structural change in the myosin filament. (5) Existence of Ca2+-induced structural changes in the thick filaments indicates possible myosin-linked regulations in the vertebrate skeletal muscle alongside with the actin-linked ones.
在松弛溶液中借助去污剂Triton X-100对青蛙缝匠肌进行脱膜处理，然后在不含ATP和钙的溶液中使其形成僵直状态（无钙僵直）。从这类肌肉获得的一些X射线衍射图谱与肌肉通常“钙”僵直状态的图谱有很大差异。对肌肉无钙僵直状态的X射线衍射图谱分析可得以下结论：（1）已证明，位于约430 Å重复周期连续阶次成组分布的所谓禁戒子午向反射是由粗肌丝中的小蛋白形成的晶格衍射所致。在解释收缩肌肉中143 Å和215 Å子午向反射的强度变化时必须考虑到这一点。（2）含肌球蛋白的肌丝轴可能存在两种不同的结构状态；这些状态之间的转变随钙浓度的变化而发生。（3）在肌球蛋白轴的两种构象中的任何一种情况下，肌球蛋白横桥都可能偏离肌丝轴。（4）肌动球蛋白僵直复合物的形成不一定会导致肌球蛋白丝的结构变化。（5）粗肌丝中存在钙诱导的结构变化表明，在脊椎动物骨骼肌中，除了与肌动蛋白相关的调节外，可能还存在与肌球蛋白相关的调节。
