Probing the mechanical properties of short molecules with optical tweezers

Structural proteins play vital roles in many human tissues, roles to which their mechanical properties are of direct relevance. Optical tweezers give us the remarkable ability to quantitatively probe these properties at the single-molecule level, potentially revealing a wealth of information on how such proteins fulfil their physiological functions. I have worked toward applying this technique, in which micron-sized beads chemically linked to the protein are manipulated by focussed laser beams, to structural proteins, particularly elastin. I developed methods to eliminate or account for several experimental complications presented by the fact that these proteins are short compared to other molecules studied with optical tweezers. I proceeded to design and test multiple strategies for linking elastin to beads, discovering that its unusual biochemical properties raise significant additional challenges. Some of these I overcame, and an assay I developed for linking effectiveness may be of use in overcoming other