Completing the myosin mechanochemical cycle with time resolved cryo EM

Project title

Completing the myosin mechanochemical cycle with time resolved cryo EM

Description

The myosin superfamily of molecular motors is essential for life, powering movement on actin filaments and muscle contraction in all eukaryotic cells. Myosin converts the energy from ATP hydrolysis into mechanical force through a process in which structural changes in separate domains of the protein are mechanically coupled to nucleotide, lever and actin binding state. The exact nature of the transitions between states and the coupling mechanism are debated as whilst various long-lived states of the cycle have been solved or trapped by crystallography or cryogenic electron microscopy (cryoEM), short-lived transition states have not. 

Our vision is to provide a step change in our fundamental understanding of how myosin functions throughout its mechanochemical cycle using cutting-edge time-resolved cryoEM. We recently took a step towards achieving this vision by solving the first primed actomyosin structure (AM.ADP.Pi), a short-lived transition state (<100ms) that could only be trapped through time-resolved approaches. This ground-breaking structure revealed how myosin initially associates with actin to generate movement and enabled us to propose how actin catalyses myosin ATPase activity. Through improvements in technology, we will now push this discovery to increased resolution to enable us to resolve fine mechanistic details and be able to resolve the missing pieces of the myosin mechanochemical cycle to high-resolution by capturing snapshots of myosin in action. By assembling these snapshots in time order we will be able to reveal the full mechanism of action of myosin and welcome you to the world of protein cinematography!