Opposites Attract in a Motor Protein


Motor proteins are fascinating cellular machines that convert chemical energy into mechanical work. They are employed in a wide range of cellular functions like muscular contraction, transportation of proteins and vesicles, and cell motility. Myosin VI is an example of a motor protein. It "walks" along actin filaments (kind of like cellular highways), performing tasks such as delivering materials across the cell. Primarily, myosin VI functions as a dimer (i.e., two myosin VI proteins are associated and form a functional complex), but the structure of the myosin VI dimer, particularly how a myosin VI associates with another one, is still debated. Teaming up with experimentalists, computational biologists investigated how two myosin VI assemble and pull their cargo together. The investigation, reported recently, focused on a segment of myosin VI that forms a long,rigid alpha-helix that is notably decorated with a distinct rings of positively and negatively charged amino acids. Carrying out single-molecule experiments along with molecular dynamics simulations using NAMD, it was found out that two myosin VI proteins attract each other electrostatically through the charge-ring proteins, shifting them such that the oppositely charged amino acids from different helices face each other. More information can be found on our motor protein website.