Nucleic Acid Enzyme-Based DNA Nanomachine for Biosensing - DNA Nanotechnology: From Structure to Function - page 298

Fig. 14.1 A directional DNA “walker” activated by enzymatic ligation and specific scission
processes (Reproduced from Ref. [ 11 ] by permission of John Wiley & Sons Ltd.)
position on the track. The concept of DNA walker was first proposed by Seeman
[ 10 ] and Pierce [ 6 ] independently. However, additional trigger strands have to be
added manually for every single walking step. This makes it difficult to achieve
autonomous and processive motions, which are important properties for an efficient
molecular walker.
Turberfield et al. developed another type of DNA walker that moves autonomous,
unidirectional along a DNA track by using DNA ligase and restriction enzymes
(Fig. 14.1 )[ 11 ]. The self-assembled track contains three anchorages at which the
walker, a six-nucleotide DNA fragment, can be bound. At each step, the walker is
ligated to the next anchorage and then cut from the previous one by a restriction
endonuclease. Each cut destroys the previous restriction site, and each ligation
creates a new site, in such a way that the walker cannot move backwards.