Evidence for cross-bridge order in contraction of glycerinated skeletal muscle.
Evidence for cross-bridge order in contraction of glycerinated skeletal muscle.
复制标题
甘油骨骼肌收缩中跨桥顺序的证据。
DOI：
10.1073/pnas.80.24.7515
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发表时间：
1983
影响因子：
11.1
通讯作者：
Borejdo,J
中科院分区：
文献类型：
--
作者：
Burghardt,TP;Ando,T;Borejdo,J
通过测量肌球蛋白头单活性巯基上的碘乙酰罗丹明标签的线性二色性，确定单甘油骨骼肌纤维中肌球蛋白交叉桥的空间取向。我们之前已经证明，在严格的发色标记是有序的，并假设一个方向几乎垂直于纤维轴；MgADP存在时，大部分探针仍保持有序，但探针姿态呈倾斜方向；在松弛的肌肉中，探针顺序大部分丢失，这意味着高度的过桥障碍。在本文中，我们报告说，在等距收缩期间，探针的很大一部分显示出高度有序，表明大约等于65%的交叉桥附着在肌动蛋白上。这些有序的交叉桥具有类似于mgadp诱导的静态状态的探针姿态，因此处于与严格状态截然不同的机械状态。
The linear dichroism of iodoacetylrhodamine labels attached to the single reactive thiol groups of myosin heads was measured to determine the spatial orientation of myosin cross-bridges in single glycerinated skeletal muscle fibers. We have shown previously that in rigor the chromophoric labels are well ordered and assume an orientation nearly perpendicular to the fiber axis; in the presence of MgADP, a large fraction of probe remains well ordered but the probe attitude assumes a more slanted orientation; in relaxed muscle, the probe order is largely lost, implying a high degree of cross-bridge disorder. In this paper, we report that during isometric contraction a large fraction of the probe shows a high degree of order, suggesting the attachment of approximately equal to 65% of the cross-bridges to actin. These ordered cross-bridges have a probe attitude similar to that of the MgADP-induced static state and hence are in a mechanical state quite distinct from rigor.