DNA-based force sensor with colorimetric detection | Molecular Force Balance

点击翻译按钮获取中文摘要

The conformational changes that many macromolecules undergo inside living cells are crucial for their biological functions. During such motions, the molecules exert and experience stretching and com-pressing forces. We propose new concepts for the measurements of forces on the piconewton scale using molecular force sensors. These sensors overcome the limitations of available force spectrosco-py techniques that require an invasive connection of the molecules with macroscopic devices such as beads or tips via long linkers. For this purpose, the powerful concepts of DNA Origami and DNA Tensegrity will be combined with established and novel single-molecule fluorescence techniques. The endeavored nanoscopic force sensors will employ the entropic force behavior of single-stranded DNA (ssDNA). The sensors will be composed of rigid DNA origami elements, which can be translocated with respect to each other. The degree of translocation will be detected optically. Therefore, photostable fluorophores and their corresponding quenchers will be attached to the DNA origami structure at designated positions. We propose concepts for nanoscopic tilting balances and spring balances. The former will enable us to measure ligand interactions in comparative assays, the latter will provide an analog readout mechanism of the sensed force: In analogy to the function of a sliding caliper, changes in distance between fluorophores of varying colors and their quenchers will lead to chromatic changes in the detected fluorescence spectrum allowing non-invasive readout of the force sensor’s state. For the future, we envision non-invasive force measurements in living cells and materials as well as new approaches to sense molecular interactions.