title: Actin binding to cross-linked 10 S smooth muscle myosin and 9 S heavy meromyosin.
abstract: Unphosphorylated gizzard myosin and heavy meromyosin were cross linked in the 10 S and 9 S states, respectively, by the cleavable cross linker, 3,3'-dithiobis (sulfosuccinimidyl-propionate) (DTSSP). The 10 S to 6 S transition for cross-linked 10 S myosin appeared to cease; myosin appeared to remain in the 10 S state from measurements of viscosity and Mg(2+)-ATPase activity. The loss of the transition for cross-linked 9 S heavy meromyosin (HMM) was also indicated by Mg(2+)-ATPase activity. The cross links were cleaved by incubation with 50 mM dithiothreitol. From direct binding measurements, the estimated Kd's of actin to cross-linked and control heavy meromyosin were 167 and 16 microM, respectively. The binding affinity of cross-linked HMM to actin was restored to the control level by dithiothreitol.
authors.affiliation: Department of Biochemistry, Sapporo Medical College, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sohma
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D003432:Cross-Linking Reagents; D004591:Electrophoresis, Polyacrylamide Gel; D005895:Gizzard, Avian; D009130:Muscle, Smooth / Q000737:chemistry; D015879:Myosin Subfragments / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism*; D013388:Succinimides / Q000737:chemistry; D014422:Turkeys
chemical_list: D000199:Actins; D003432:Cross-Linking Reagents; D015879:Myosin Subfragments; D013388:Succinimides; C035759:3,3'-dithiobis(sulfosuccinimidyl propionate); D017301:Ca(2+) Mg(2+)-ATPase; D009218:Myosins