Single DNA molecule manipulation by a self-assembled motor protein system

A lambdaDNA manipulation by motor proteins has been demonstrated by designing a fully self-assembled molecular system. Each end of lambdaDNA was modified by biotin and digoxin, respectively, based on fragment labeling and ligation methods. Digoxin-functionalized end was immobilized on a glass surface coated with anti-digoxigenin antibody. Biotinylated end was freely suspended and experienced Brownian motion in a buffer solution. Streptavidin was introduced to the biotinylated end for the binding with motile biotinylated microtubules. Infusing kinesin and biotinylated microtubules into the system cause microtubule gliding assay on the kinesin-coated surface. During the assay microtubules picked up the streptavidin-labeled end of DNA by biotin and streptavidin binding. It brought the DNA stretching and the phenomena were finally terminated by a release of molecular binding or DNA breakage. The total length achieved over 20 mum, which is the same as DNA contour length.