Mechanobiology is an emerging multidisciplinary field that investigates how physical forces and changes in the mechanical properties of cells and tissues contribute to biological processes, including development, cell differentiation, physiology, and disease.
Proteins are essential to life, carrying out key tasks in cells. How proteins acquire their functional folded native state, in particular when they repeatedly unfold and refold in their biological setting, remains a central question in biology. Machine learning has advanced the field by accurately predicting protein structure, but experimental observation is still required to understand how the structures form.
Writing in Nature Physics, LCN Researchers at King’s College London report that they observed the folding dynamics of a single protein over much longer timescales than earlier experiments, up to several days, enabling them to probe previously inaccessible states.
Using force spectroscopy, Dr Rafael Tapia-Rojo and a team of researchers probed the protein folding in talin, a protein fundamental to converting mechanical stimulus into biochemical activity in the body. They designed a new magnetic tweezers assay, where they tethered a single molecule to measure its conformational dynamics under force. As you would expect, the protein unfolded when under high force and folded under low force and fluctuated between both states when under an intermediate force.
When measured over classically probed timescales, the protein switched between these two states, folded and unfolded, in agreement with previous observations. However, as the duration of the experiment increased, the protein exhibited gradually higher signatures of complexity, populating new rare conformational structures inaccessible with previous instrumentation. Importantly, when trapped in one of these low-probability states, talin loses its biological function—meaning that it is incapable of recruiting its key binding partner, vinculin—resonating with the classical notion of a misfolded state.
With previous experimental assays, we could observe a single molecule under force for a few seconds or minutes, which gave us a limited understanding of its dynamic behavior. Thanks to this novel magnetic tweezers development, we can now watch a single protein folding for several hours or even days, allowing us to capture previously inaccessible events. This new approach opens new avenues to understanding how proteins behave over long timescales, for instance, enabling us to observe proteins aging in real-time and describe how their malfunctioning is linked to such aged condition Lead Author - Dr Tapia-Rojo
This new enabling experimental assay offers new ways to study protein folding and, in particular, to directly capture and interrogate protein misfolded structures, which underpins a significant number of diseases.
'Enhanced statistical sampling reveals microscopic complexity in the talin mechanosensor folding energy landscape' is published in Nature Physics
