Coy D L, Hancock W O, Wagenbach M, Howard J
Department of Physiology & Biophysics, University of Washington, Seattle 98195-7290, USA.
Nat Cell Biol. 1999 Sep;1(5):288-92. doi: 10.1038/13001.
When not bound to cargo, the motor protein kinesin is in an inhibited state that has low microtubule-stimulated ATPase activity. Inhibition serves to minimize the dissipation of ATP and to prevent mislocalization of kinesin in the cell. Here we show that this inhibition is relieved when kinesin binds to an artificial cargo. Inhibition is mediated by kinesin's tail domain: deletion of the tail activates the ATPase without need of cargo binding, and inhibition is re-established by addition of exogenous tall peptide. Both ATPase and motility assays indicate that the tail does not prevent kinesin from binding to microtubules, but rather reduces the motor's stepping rate.
当不与货物结合时，驱动蛋白这种运动蛋白处于抑制状态，其微管刺激的ATP酶活性较低。抑制作用有助于将ATP的消耗降至最低，并防止驱动蛋白在细胞中错误定位。我们在此表明，当驱动蛋白与人工货物结合时，这种抑制作用会解除。抑制作用由驱动蛋白的尾部结构域介导：删除尾部可激活ATP酶，而无需货物结合，通过添加外源性尾部肽可重新建立抑制作用。ATP酶和运动分析均表明，尾部不会阻止驱动蛋白与微管结合，而是会降低驱动蛋白的步移速率。
