Processive behaviour of kinesin observed using micro-fabricated cantilevers
Processive behaviour of kinesin observed using micro-fabricated cantilevers
复制标题
使用微制造悬臂观察驱动蛋白的加工行为
DOI：
10.1088/0957-4484/22/9/095707
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发表时间：
2011
期刊：
影响因子：
3.5
通讯作者：
M. Antognozzi
中科院分区：
文献类型：
--
作者：
T. Scholz;J. Vicary;G. M. Jeppesen;A. Ulčinas;J. Hörber;M. Antognozzi
生物分子马达的机械特性需要具有亚皮牛顿分辨率的力传感器。纳米级马达与这类微型传感器的耦合根据传感器的热激活自由度在马达中引入了结构变形。目前，还没有简单的解决方案来减少这些影响。在这里，我们利用微制造悬臂梁的优势，制作了一种基本上只有一个自由度的力传感器，其弹性常数为0.03pN nm−1，用于研究分子马达蛋白Kinesin-1。在过程运行过程中，悬臂限制了Kinesin的货物结合结构域在平行于微管轨道的直线上的移动，并排除了特定的反应坐标，如货物旋转。在此条件下，我们测得饱和三磷酸腺苷浓度下S−-1的步长为8.0±0.4 nm，最大卸载速度为82 0±80 nm。我们得出的结论是，马达在连续的步进周期中移动时，不需要旋转尾巴。
The mechanical characterization of biomolecular motors requires force sensors with sub-piconewton resolution. The coupling of a nanoscale motor to this type of microscale sensors introduces structural deformations in the motor according to the thermally activated degrees of freedom of the sensor. At present, no simple solution is available to reduce these effects. Here, we exploit the advantages of micro-fabricated cantilevers to produce a force sensor with essentially one degree of freedom and a spring constant of 0.03 pN nm − 1 for the study of the molecular motor protein kinesin-1. During processive runs, the cantilever constrains the movement of the cargo binding domain of kinesin in a straight line, parallel to the microtubule track, and excludes specific reaction coordinates such as cargo rotation. In these conditions, we measured a step size of 8.0 ± 0.4 nm and a maximal unloaded velocity of 820 ± 80 nm s − 1 at saturated adenosine triphosphate (ATP) concentration. We concluded that the motor does not need to rotate its tail as it moves through consecutive stepping cycles.