In vitro motility of proteolytically cleaved myosin subfragment 1 on a lysine-coated surface

The in vitro motility of enzymatically cleaved S-1 was investigated with a novel procedure for the coating of a glass surface with poly-L-lysine. On a lysine-coated surface, HMM and S-1 (mixture of 95 and 91 kDa fragments) moved F-actin filaments at average velocities of 4.41 and 1.54 microns/s, respectively, which are similar to those, 5.96 and 1.47 microns/s, on a collodion-coated surface, respectively. Myosin S-1 composed of the 91 kDa polypeptide could move F-actin at 1.15 microns/s. Tryptically cleaved chymotryptic S-1 could move F-actin filaments at an average velocity of 2.8 microns/s: about 2 times that in the case of S-1. This activation of the sliding movement on cleaved S-1 arises partly from reduction of the drag force due to the low affinity of cleaved S-1 for F-actin. The motility of S-1 cleaved at other sites was also examined on a lysine-coated surface.