Measuring the force of adhesion between multiple kinesins and a microtubule using the fluid force produced by microfluidic flow

作者：Yokokawa Ryuji^*; Sakai Yusuke; Okonogi Atsuhito; Kanno Isaku; Kotera Hidetoshi

来源：Microfluidics and Nanofluidics, 2011, 11(5): 519-527.

DOI：10.1007/s10404-011-0817-2

• Microfluidics
• Protein binding
• Mechanical modeling
• Micro total analysis systems (MicroTAS)
• Molecular transport

We developed a method to measure the adhesion force between the motor protein, kinesin, and a microtubule. Compared with conventional methods that use optical tweezers, our method employs the fluid force that acts on the interaction between a kinesin-coated microbead and a microtubule in a microfluidic channel. When the fluid force just exceeds the kinesin-microtubule adhesion force, the beads are released from the microtubules. Having modeled the kinesins that are bound to the microtubules and the beads as mechanical springs, adhesion forces were measured as 31.3 or 362.9 pN for fluid containing 1 mM ATP or 0 M ATP, respectively. These forces are much larger than those measured when optical tweezers were used to measure the adhesion force between a single kinesin and a microtubule. For our multi-kinesin system we elucidated the relationship between the binding force of a single kinesin molecule and that of all kinesin molecules in a contact area by varying one of two parameters: either the contact area length or the kinesin density on a bead. This study provides insight into the behavior of a bead that is supported by several kinesins in a microfluidic system, which is essential knowledge if a motor protein is to be used as a nanoactuator for in vitro molecular transport.

• 出版日期2011-11