Rescue of in vitro actin motility halted at high ionic strength by reduction of ATP to submicromolar levels.
Rescue of in vitro actin motility halted at high ionic strength by reduction of ATP to submicromolar levels.
复制标题
通过将 ATP 降低至亚微摩尔水平，在高离子强度下停止体外肌动蛋白运动的挽救。
DOI：
10.1016/s0005-2728(96)00089-8
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Pollack,GH
中科院分区：
文献类型：
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作者：
Kellermayer,MS;Pollack,GH
ATP浓度和离子强度的综合影响进行了研究，在肌动球蛋白在体外运动试验中使用骨骼肌和心肌肌球蛋白。肌动蛋白丝的速度增加到一个临界离子强度，在此长丝滑动停止。在临界离子强度或以上，细丝不滑动，但摆动，同时局部附着在表面上。在这些高离子强度下，当ATP浓度（最初为1 mM）通过严格溶液洗涤逐渐降低（降至亚微摩尔水平）时，静止的、摆动的肌动蛋白丝迅速开始滑动。这种效应是可逆的;再次加入ATP后，滑动运动停止，开始摆动。ATP洗脱诱导的运动在高离子强度可以解释由静电机制决定的亲和力的肌球蛋白肌动蛋白。骨骼肌和心肌肌球蛋白的临界离子强度不同。对于骨骼肌，它是77 mM，而对于心脏，它只有57 mM。心脏肌球蛋白的临界离子强度较低意味着较低的亲和力肌动蛋白。
The combined effects of ATP concentration and ionic strength were studied in an actomyosin in vitro motility assay using skeletal and cardiac myosin. The velocity of actin filaments increased up to a critical ionic strength, at which filament sliding stopped. At or above the critical ionic strength, filaments did not slide, but wiggled while focally attached to the surface. At these high ionic strengths, when the ATP concentration (originally 1 mM) was progressively reduced (down to submicromolar levels) by rigor-solution washes, the stationary, wiggling actin filaments promptly started to slide. The effect was reversible; upon adding ATP again, the sliding movement stopped, and wiggling began. The ATP washout-induced motility at high ionic strength may be explained by an electrostatic mechanism which determines the affinity of myosin to actin. The critical ionic strength was different for skeletal and cardiac myosin. For skeletal it was 77 mM, while for cardiac it was only 57 mM. Cardiac myosin's lower critical ionic strength implies a lower affinity to actin.