Key residues on microtubule responsible for activation of kinesin ATPase
Key residues on microtubule responsible for activation of kinesin ATPase
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DOI：
10.1038/emboj.2010.25
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发表时间：
2010-04-07
期刊：
影响因子：
11.4
通讯作者：
Muto, Etsuko
中科院分区：
文献类型：
--
作者：
Uchimura, Seiichi;Oguchi, Yusuke;Muto, Etsuko
微管（MT）结合加速驱动蛋白中ATP水解的速率。为了理解潜在的机制，使用电荷-丙氨酸突变分析，我们确定了微管蛋白中的两个独立位点，这对驱动蛋白运动性至关重要，即，跨越α-微管蛋白的螺旋11-12（H11-12）环和H12的带负电荷的残基簇，以及β-微管蛋白的H12中的带负电荷的残基。α-微管蛋白结合位点的突变导致ATP水解的减速（k（cat）），而β-微管蛋白结合位点的突变降低了对MT的亲和力（K（0.5）MT）。α-微管蛋白中的残基E415似乎对于MT结合和ATP酶激活的偶联很重要，因为该位点的突变导致ATP水解的总体速率急剧降低，这主要是由于ADP释放反应的减速。我们的研究结果表明，驱动蛋白结合在一个区域含有α-E415可以传递信号的驱动蛋白核苷酸口袋，触发其构象变化，并导致ADP的释放。The EMBO Journal（2010）29，1167-1175. doi：10.1038/doj.2010.25; 2010年3月11日在线发布
Microtubule (MT) binding accelerates the rate of ATP hydrolysis in kinesin. To understand the underlying mechanism, using charged-to-alanine mutational analysis, we identified two independent sites in tubulin, which are critical for kinesin motility, namely, a cluster of negatively charged residues spanning the helix 11-12 (H11-12) loop and H12 of alpha-tubulin, and the negatively charged residues in H12 of beta-tubulin. Mutation in the alpha-tubulin-binding site results in a deceleration of ATP hydrolysis (k(cat)), whereas mutation in the beta-tubulin-binding site lowers the affinity for MTs (K(0.5)MT). The residue E415 in alpha-tubulin seems to be important for coupling MT binding and ATPase activation, because the mutation at this site results in a drastic reduction in the overall rate of ATP hydrolysis, largely due to a deceleration in the reaction of ADP release. Our results suggest that kinesin binding at a region containing alpha-E415 could transmit a signal to the kinesin nucleotide pocket, triggering its conformational change and leading to the release of ADP. The EMBO Journal (2010) 29, 1167-1175. doi:10.1038/emboj.2010.25; Published online 11 March 2010