Yokota E, Mabuchi I, Sato H
Department of Cell Biology, National Institute for Basic Biology, Aichi.
J Biochem. 1987 Jul;102(1):31-41. doi: 10.1093/oxfordjournals.jbchem.a122038.
When 21S dynein ATPase [EC 3.6.1.3] from sea urchin sperm flagellar axonemes was mixed with the salt-extracted axonemes, the ATPase activity was much higher than the sum of ATPase activities in the two fractions, as reported previously (Gibbons, I.R. & Fronk, E. (1979) J. Biol. Chem. 254, 187-196). This high ATPase level was for the first time demonstrated to be due to the activation of the 21S dynein ATPase activity by the axonemes. The mode of the activation was studied to get an insight into the mechanism of dynein-microtubule interaction. The salt-extracted axonemes caused a 7- to 8-fold activation of the 21S dynein ATPase activity at an axoneme : dynein weight ratio of about 14 : 1. The activation was maximal at a low ionic strength (no KCl) at pH 7.9-8.3. Under these conditions, 21S dynein rebound to the salt-extracted axonemes. The maximal binding ratio of 21S dynein to the axonemes was the same as that observed in the maximal activation of 21S dynein ATPase. The sliding between the outer doublet microtubules in the trypsin-treated 21S dynein-rebound axonemes took place upon the addition of 0.05-0.1 mM ATP in the absence of KCl. During the sliding, the rate of ATP hydrolysis was at the same level as that of the 21S dynein activated by the salt-extracted axonemes. However, it decreased to the level of 21S dynein alone after the sliding. These results suggested that an interaction of the axoneme-rebound 21S dynein with B-subfibers of the adjacent outer doublet microtubules in the axoneme causes the activation of the ATPase activity.
当将海胆精子鞭毛轴丝中的21S动力蛋白ATP酶[EC 3.6.1.3]与经盐抽提的轴丝混合时，ATP酶活性比两个组分中ATP酶活性之和高得多，如先前报道（吉本斯，I.R.和弗龙克，E.（1979年）《生物化学杂志》254卷，第187 - 196页）。首次证明这种高ATP酶水平是由于轴丝对21S动力蛋白ATP酶活性的激活。研究了激活模式以深入了解动力蛋白 - 微管相互作用的机制。经盐抽提的轴丝在轴丝与动力蛋白重量比约为14∶1时，使21S动力蛋白ATP酶活性激活7至8倍。在pH 7.9 - 8.3的低离子强度（无氯化钾）下激活作用最大。在这些条件下，21S动力蛋白反弹至经盐抽提的轴丝上。21S动力蛋白与轴丝的最大结合比与在21S动力蛋白ATP酶最大激活时观察到的相同。在胰蛋白酶处理的21S动力蛋白反弹的轴丝中，当在无氯化钾的情况下加入0.05 - 0.1 mM ATP时，外双联微管之间发生滑动。在滑动过程中，ATP水解速率与经盐抽提的轴丝激活的21S动力蛋白的水解速率处于同一水平。然而，滑动后它降至单独的21S动力蛋白的水平。这些结果表明，轴丝反弹的21S动力蛋白与轴丝中相邻外双联微管的B亚纤维相互作用导致ATP酶活性的激活。
