The alanine-scanning mutagenesis of Dictyostelium myosin II at the ionic interface with actin.

Abstract

Cyclic interaction of actin and myosin coupled with ATP hydrolysis is essential for generation of force by the actin-myosin system. The major force maintaining the actin-myosin contact during ATP hydrolysis, actin-myosin sliding and force generation seems to be ionic interactions, since these functions are highly sensitive to the ionic strength of the solvent. In the absence of ATP, i.e., under rigor conditions, however, hydrophobic interactions become dominant in maintaining the actin-myosin association. Based on the three-dimensional reconstruction of electron microscopic images of the rigor complex of actin and myosin subfragment 1 (S1), these ionic and hydrophobic interaction sites have been tentatively assigned to several locations of actin and myosin (Schroder et al. 1993; Milligan 1996).KeywordsActin FilamentMalachite GreenBasic ResidueHeavy Chain GeneDictyostelium CellThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.