Naber Nariman, Minehardt Todd J, Rice Sarah, Chen Xiaoru, Grammer Jean, Matuska Marija, Vale Ronald D, Kollman Peter A, Car Roberto, Yount Ralph G, Cooke Roger, Pate Edward
Department of Biochemistry, University of California, San Francisco, CA 94143, USA.
Science. 2003 May 2;300(5620):798-801. doi: 10.1126/science.1082374.
We have used adenosine diphosphate analogs containing electron paramagnetic resonance (EPR) spin moieties and EPR spectroscopy to show that the nucleotide-binding site of kinesin-family motors closes when the motor.diphosphate complex binds to microtubules. Structural analyses demonstrate that a domain movement in the switch 1 region at the nucleotide site, homologous to domain movements in the switch 1 region in the G proteins [heterotrimeric guanine nucleotide-binding proteins], explains the EPR data. The switch movement primes the motor both for the free energy-yielding nucleotide hydrolysis reaction and for subsequent conformational changes that are crucial for the generation of force and directed motion along the microtubule.
我们使用了含有电子顺磁共振（EPR）自旋部分的二磷酸腺苷类似物以及EPR光谱来表明，当驱动蛋白家族马达的二磷酸复合物与微管结合时，其核苷酸结合位点会关闭。结构分析表明，核苷酸位点处开关1区域的结构域运动，与G蛋白[异源三聚体鸟嘌呤核苷酸结合蛋白]中开关1区域的结构域运动同源，这解释了EPR数据。这种开关运动使马达既为产生自由能的核苷酸水解反应做好准备，也为随后对沿微管产生力和定向运动至关重要的构象变化做好准备。
