In vitro ATP-dependent F-actin sliding on myosin is not influenced by substitution or removal of bound nucleotide.

To examine possible role of F-actin-bound nucleotide in ATP-dependent actin-myosin sliding, we prepared various actin filaments with different nucleotide contents and compared their sliding velocities on heavy mero-myosin in the presence of 2'-deoxyadenosine 5'-triphosphate (dATP) to exclude possible exchange of external ATP with the actin-bound nucleotide. Neither the sliding velocity nor the length of the actin filaments was significantly influenced by substitution or removal of actin-bound nucleotide, indicating that actin-bound nucleotide may not play a significant role in the sliding between actin and myosin.