FLUCTUATIONS IN POLARIZED FLUORESCENCE - EVIDENCE THAT MUSCLE CROSS BRIDGES ROTATE REPETITIVELY DURING CONTRACTION
FLUCTUATIONS IN POLARIZED FLUORESCENCE - EVIDENCE THAT MUSCLE CROSS BRIDGES ROTATE REPETITIVELY DURING CONTRACTION
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DOI：
10.1073/pnas.76.12.6346
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发表时间：
1979-01-01
影响因子：
11.1
通讯作者：
MORALES, MF
中科院分区：
文献类型：
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作者：
BOREJDO, J;PUTNAM, S;MORALES, MF
单甘油化肌纤维的肌球蛋白亚片段 1 部分的特定硫醇用罗丹明共价标记。通过使用适当的解决方案，这些纤维可以松弛、紧绷或产生主动等长张力。罗丹明由 514.5 nm 偏振激光激发； > 580 nm 荧光被分解为正交分量，每个分量的强度均由计算机接口的光子计数系统测量。超过噪音的波动出现在稳态活动中，但在放松或严格状态下不会出现，并且当荧光团附着在肌动蛋白而不是肌球蛋白上时不会出现。波动也出现在对荧光团态度敏感但对荧光团数量不敏感的偏振强度-数量的比率中。波动主要由低频率（约 2 Hz）主导，类似于单独测量的 ATP 酶频率。这些波动归因于罗丹明所附着的横桥的重复运动。
Particular thiols of the myosin subfragment 1 moieties of single glycerinated muscle fibers are covalently labeled with rhodamine. By using appropriate solutions such fibers can be relaxed, be in rigor, or develop active isometric tension. The rhodamine is excited by polarized 514.5-nm laser light; the > 580-nm fluorescence is resolved into orthogonal components and the intensity of each is measured by a computer-interfaced photon counting system. Fluctuations over and-above noise appear in steady-state activity but not in relaxation or rigor and not when the fluorophore is actin-attached instead of myosin-attached. Fluctuations also appear in ratios of polarized intensities-quantities sensitive to fluorophore attitude but not to fluorophore number. The fluctuations are dominated by low (.apprxeq. 2 Hz) frequencies similar to separately measured ATPase frequencies. The flucuations are ascribed to repetitive motion of the cross bridges to which the rhodamine is attached.