Using optical tweezers to study the fine details of myosin ATPase mechanochemical cycle.

Optical tweezers offer the capability to directly observe nanometre displacements and apply piconewton forces to single proteins. This method has been applied to the study of many different biological systems. Optical tweezers have proven to be particularly useful in studying the fine details of the mechanisms of molecular motor proteins, and how their movement is coordinated with ATPase activity. This includes actin, microtubule, and also DNA- and RNA-based motor systems. Here, we provide the information necessary to reproduce the "three-bead geometry" widely applied to the study of actomyosin interactions, the "paradigm system" for motors that only interact intermittently with their filament substrate, and discuss how single-molecule interactions can be detected, calibrated and analysed.