ANALYSIS OF SINGLE TURNOVERS IN THE CAGED-ATP EXPERIMENT ON SKINNED MUSCLE FIBERS

皮肌纤维笼内 ATP 实验中单次转换的分析

• 批准号: 09670050
• 负责人: HORIUTI Keisuke
• 金额: $ 1.92万
• 依托单位: OITA MEDICAL UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09670050/
• 关键词: skeletal muscle; contraction; skinned fiber; cross-bridge; caged ATP; photolysis; x-ray diffraction; synchrotron radiation; 骨格節

A mechanical study on skinned rat muscle fibres was performed at <approximately equal> 16ﾟC involving x-ray diffraction and caged-ATP photolysis ; the amounts of photoreleased ATP were set lower than 0.2 mM.The main aim was to analyze the deactivation process in single turnovers of the cross-bridge ATPase. With regard to the phase of activation, the results under the single turnover condilions were generally consistent with our previous results obtained with larger amounts of photoreleased ATP.The mechanical activity of the muscle was monitored by the 90ﾟ-out-of-phase component of stiffness at 500 Hz. In the phase of deactivation, this stiffness decreased to zero with a t_<1/2> of 0.2-0.3 s. Judging from intensities of the x-ray reflections, a large number of cross-bridges turned into the strong binding structure with a t112 of 0.5-0.7 s. However, at this time, tension did not increase but was slowly decreasing with a t_<1/2> of <approximately equal>1.0 s. Our results indicate that many of the cross-bridges are not in the strong binding state during contraction, and that they produce little force even when they are deactivated and take the strong binding conformatio

在16 ℃下进行了机械研究，涉及X-射线衍射和笼状ATP光解的皮肤大鼠肌纤维，光释放的ATP的量被设置为低于0.2 mM。主要目的是分析失活过程中的单周转的跨桥ATP酶。<approximately equal>就激活阶段而言，单次转换条件下的结果与我们之前在大量光释放ATP的情况下获得的结果基本一致。肌肉的机械活动通过90 °的反相分量来监测。500 Hz的刚度。在失活阶段，该刚度在t1/2为0.2-0.3 s时降至零。从X射线反射强度判断，大量的交叉桥转变为强结合结构，t112为0.5 - 0.7 s。但此时张力没有增加，而是缓慢下降，t1/2&gt;为1.0 s。<approximately equal>结果表明，许多横桥在收缩过程中并不处于强结合状态，即使它们失活并采取强结合构象，它们也几乎不产生力。

项目成果

堀内,八木,竹森: "筋線維内クロスブリッジのATPアーゼ-回転" 生物物理. 37・S2. S205 (1997)

Horiuchi、Yagi、Takemori：“肌内横桥的 ATP 酶旋转”生物物理学 37·S2（1997）。

K.Horiuti, N.Yagi, S.Takemori: "Single turnover of the cross-bridge ATPase in muscle fibers : Dissociation between the rigor-bond formation and tension development." Biophysics (Tokyo). 37. S205 (1997)

K.Horiuti、N.Yagi、S.Takemori：“肌纤维中跨桥 ATP 酶的单周转：紧密结合形成与张力发展之间的分离。”

堀内,八木,竹森: "筋線維内クロスブリッジのATPアーゼ-回転" 生物物理. 37,S2. S205 (1997)

Horiuchi、Yagi、Takemori：“肌肉内横桥的 ATP 酶旋转”生物物理学 37，S2。

堀内桂輔: "ケージドATP光分解でおこしたラット筋Ca^<2+>感受性一過的収縮へのADP・・・" 生物物理. 38,S2. S197 (1998)

Keisuke Horiuchi：“ADP 对由笼内 ATP 光解引起的大鼠肌肉 Ca 2+ 敏感的瞬时收缩......”生物物理学 38，S2（1998）。