Biomolecules and nanostructures
The Optical Sciences group studies the interaction of light and matter at the nanoscale.
We do this by exploring ways to shape light and its environment. It's what we call
active and passive control. Our current focus is on the interaction of light with
biomolecules and nanostructures. We are part of Twente
University's Department of Science and Technology and member of the
Direct visualization of dynamic protein-DNA interactions with a dedicated atomic force microscope
van Noort SJT, van der Werf KO, Eker APM, Wyman C, de Grooth BG, van Hulst NF, Greve J
vol 74 issue 6: p2840-p2849 JUN 1998
Photolyase DNA interactions and the annealing of restriction fragment ends are directly visualized with the atomic force microscope (AFM). To be able to interact with proteins, DNA must be loosely bound to the surface. When MgCl2 is used to immobilize DNA to mica, DNA is attached to the surface at distinct sites. The pieces of DNA in between are free to move over the surface and are available for protein interaction. After implementation of a number of instrumental improvements, the molecules can be visualized routinely, under physiological conditions and with molecular resolution. Images are acquired reproducibly without visible damage for at least 30 min, at a scan rate of 2 x 2 mu m(2)/min and a root mean square noise of less than 0.2 nm. Nonspecific photolyase DNA complexes were visualized, showing association, dissociation, and movement of photolyase over the DNA. The latter result suggests a sliding mechanism by which photolyase can scan DNA for damaged sites. The experiments illustrate the potential that AFM presents for modern molecular biology.