A simple method to deposit elongated DNA onto fused-silica surfaces for single molecule studies of protein-DNA interactions

In order to study facilitated diffusion of proteins along DNA using single molecule fluorescence imaging methods, it is necessary to deposit elongated DNA molecules along fused-silica surfaces [1]. Here we have developed a simple method to deposit elongated DNA molecules onto fused-silica surfaces with high yield. We attached the ends of DNA molecules to streptavidin coated quantum dots and then deposited the end-labeled DNA onto fused-silica surfaces. The flow created by a cover slip is adequate to generate arrays of elongated and suspended DNA anchored by the two ends of each molecule, ideal for protein-DNA interaction studies. Interactions of LacI with these elongated DNA molecules will also be discussed. \newline \newline [1] Y. M. Wang, E. C. Cox and R. Austin, ``Single molecule measurements of repressor proteins 1D diffusion on DNA,'' Phys. Rev. Lett., 97, 048302, (2006).