X-ray structures of the MgADP, MgATPgammaS, and MgAMPPNP complexes of the Dictyostelium discoideum myosin motor domain

The three-dimensional structures of the truncated myosin head from Dictyostelium discoideum myosin II (S 1 dC) complexed with MgAMPPNP, MgATPgammaS and MgADP were investigated. The overall structures of all three complexes were very close to that of the beryllium fluoride complex. This indicates that the differences in the physiological effects of ATPgammaS and AMPPNP are caused by alterations in the equilibrium between the actin-bound and actin-free states of myosin due to the lower affinity of AMPPNP for myosin.