Mechanism of Phosphate Release from Actin Filaments.

in the active site is rate limiting owing to a large free energy barrier 20 kcal/mol. Release of phosphate from the protein requires opening a gate in the actin molecule formed by interaction of the sidechains of arginine 177 and asparagine 111. Surprisingly, the simulations revealed other interactions of the sidechain of arginine 177 that occlude the release pathway most of the time but have not been observed in cryo-EM structures. (124 words).