Overview of Project

Figure 2 DNA translocation

(a) The DNA-binding molecular motor binds to DNA, which is attached to a surface, at a specific DNA sequence unique to each motor. (b) The motor ‘pulls’ the DNA through the bound complex toward both the surface and the bound motor. (c) Pulling the DNA also pulls the bound magnetic bead toward the motor. (d) The motor stops at the bead and the motor subunit is released resetting the nanoactuator. (e) After resetting fresh motor protein will allow the nanoactuator to be reused (Firman, 1999; Seidel et al., 2004)

The original concept of a simple study of DNA translocation was expanded to include the concept of demonstrating the feasibility of building a device, around the concept of a biological molecular motor ‘pulling’ DNA and an attached magnetic bead, which would sense electronically the moving magnet – producing a nanoactuator that links the biological and silicon worlds. Alternative motors were to be studied in case too much emphasis on one motor stopped the project ‘dead in its tracks’. In addition, the project was expanded to study fluorescence as an alternative to moving magnets for detecting the movement of the DNA, with a long-term goal of single-molecule DNA sequencing. Finally, additional input was allowed to study device design, magnetic bead design etc. The result was a highly ambitious FET-OPEN project, which, many people did not expect to succeed much beyond a demonstration of molecular movement by maybe one or two molecular motors. However, the progress toward demonstrating motor activity for both EcoR124I (at TUDelft) and with other motors (at ENS/CNRS) was rapid and highly productive and at the end of Year 1 we had shown that two motors (EcoR124I and FtsK) were very able to pull the commercial 1 micron magnetic beads used in the Magnetic Tweezer Setup. By the end of Year 2 we had fully characterised these two motors and demonstrated the use of microfluidics with the Magnetic Tweezer system. Therefore, at the beginning of Year 3 we were perfectly positioned to demonstrate Proof of Principle of the proposed Mol Switch Device despite the original complexity of the Project.