Transport of semiconductor nanocrystals by kinesin molecular motors
Transport of semiconductor nanocrystals by kinesin molecular motors
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DOI：
10.1002/smll.200500223
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发表时间：
2006-05-01
期刊：
影响因子：
13.3
通讯作者：
Hancock, WO
中科院分区：
文献类型：
--
作者：
Muthukrishnan, G;Hutchins, BM;Hancock, WO
动蛋白分子马达利用ATP水解的能量，沿着细胞内的微管运输囊泡和细胞器等货物。通过将电机和细丝集成到MEMS和NEMS设备中，该系统的纯化组件可以用于纳米级的运输。因此，了解这些蛋白质的功能对于生物、治疗和纳米技术应用是很重要的。现有的研究马达的技术包括微管滑动分析、光学陷阱、[6]和ATPase分析。[7]单分子可视化对于研究马达的机制及其移动和组装纳米粒子的能力至关重要。[8-10]在这篇报告中，我们合成了半导体纳米晶体，将它们连接到动蛋白上，证明了单个马达可以通过简单的荧光或消逝波显微镜进行可视化，并表明单个马达的运动功能不受粒子功能化的影响。用绿色荧光蛋白(GFP)或合成的荧光团作用的单个马达可以通过全反射荧光(TIRF)显微镜进行成像，[8]它们的位置被分辨到近一纳米范围内。[11]通过跟踪标记了两个运动域(头)之一的运动蛋白，这项技术被用来表明在限制ATP浓度时，每个头沿着微管走16纳米的步，排除了运动蛋白运动的“尺寸虫”模型。[11]然而，由于空间分辨率是基于收集的光子的数量，使用这些荧光团的时间分辨率是有限的。
Kinesin molecular motors harness the energy of ATP hydrolysis to transport cargo such as vesicles and organelles along intracellular microtubules. Purified components of this system can be used for nanoscale transport by integrating the motors and filaments into MEMS and NEMS devices.[1–4] Hence, it is important to understand the function of these proteins for biological, therapeutic, and nanotechnological applications. Existing techniques for studying motors include the microtubule gliding assay,[5] optical traps,[6] and ATPase assays.[7] Single-molecule visualization is crucial for investigating the motor mechanism and their ability to move and assemble nanoparticles.[8–10] In this report, we synthesize semiconductor nanocrystals, attach them to kinesins, demonstrate that single motors can be visualized by simple epifluorescence or evanescent wave microscopy, and show that motor function is unaffected by particle functionalization.Single kinesin motors functionalized with green fluorescent protein (GFP) or synthetic fluorophores can be imaged by total internal reflection fluorescence (TIRF) microscopy,[8] and their position resolved to within nearly one nanometer.[11] By tracking kinesins in which one of the two motor domains (heads) was labeled, this technique was used to show that at limiting ATP concentrations each head takes 16-nm steps along a microtubule, ruling out the “inchworm” model of kinesin motility.[11] However, because the spatial resolution is based on the number of photons collected, the temporal resolution using these fluorophores is limit-