蛋白質馬達與細胞骨架交互作用之模擬 - 微管輸送器的運動模擬

Abstract

於細胞體內，驅動蛋白與微管是非常重要的機能性酵素，同時也是自然界即存在的奈米級馬達。由於其於生物體外仍具有的一些優點，例如：尺寸大小、高效率的化學能與動能轉換(三磷酸腺苷酶)以及穩固的移動模式，致使這些奈米馬達可以應用於微米尺寸活動的人造機械。在近年來許多研究中，此概念被提出並且實行於設計許多不同種類的生物感測器或者微米/奈米尺寸的設備，然而對於其中細節部分的力學現象仍未被釐清，因此我們在研究了驅動蛋白與微管的機能後設計出簡化模型以模擬微管與微米構造物間的交互作用。於本篇論文結果中可證明，生物體外如欲達到高效率的微管輸送器之引導作用，微流道中所鋪設的驅動蛋白密度是影響其運作表現的關鍵要素之一。當微管於流道中運動並與側邊牆面碰撞時，高密度的底部驅動蛋白鋪設可使微管不易脫離流道而能夠持續被驅動蛋白所捕捉並且沿牆面引導。如利用外加電場控制微管於微流道中的運動，低密度的底面驅動蛋白鋪設反而能導致高效率的控制效果。這些由模擬結果所證明之應用概念將可作為未來設計與研究驅動蛋白及微管所建立的微流道設施之重要指標。

Kinesins and microtubules are important functional enzymes in cells and truly nano-motors. With the advantages of their size, high chemo-mechanical transduction efficiency (ATPase), and robust movement in vitro it is intriguing to integrate these nano-motors with artificial machines for micro-scale actuations. Many studies proposed and implemented this concept to design different kinds of bio-sensors or other micro-/ nano-scale devices recently. However, the detailed mechanistic behavior has not been proposed and discussed. We studied the functionality of kinesin and microtubule and proposed a simplified model of the interaction between microtubules and micro-machined structures. In the result of this thesis, in order to have high efficiency of microtubule guiding in vitro, the density of kinesins coated on the bottom surface in the microfluidic channel influences the behavior of guided microtubule movement. In case of microtubule collision with channel sidewall, the density of kinesins coated on the surface nearby the sidewall should be as higher as possible to make microtubule easy to be recaptured by next functional kinesin and then keep guided by the wall. On the other hand, to control the microtubule movement by adding electric field, the guiding efficiency is relatively high in lower density of kinesins coated on the plane surface. These results of modeling microtubule movement can become a guideline for future study of microtubule guiding technology in microfluidic channel.