Scientists can use optical tweezers to trap beads and catch a biomolecule, such as a protein, in between. The folding and unfolding of the protein can then be monitored by moving the beads while measuring the force and extension. The combination of optical tweezers with simultaneous multicolor fluorescence measurements (e.g. with FRET) allows correlating the global mechanical properties of the protein with the local structural properties.

With optical tweezers – fluorescence microscopy you can:

• Investigate protein folding and unfolding in real time, at the single molecule level and with high resolution
• Measure highly detailed equilibrium dynamics over long periods of time to identify the protein (un)folding pathway and map the energy landscape
• Correlate global mechanical properties of the protein with local structural properties
• Perform experiments under biologically relevant conditions and highly crowded environments and link the in vitro experiment with the in vivo situation
• Study the effect of small molecules and biologics in protein structure and dynamics.

See the more detailed application note here