The binding of heat-treated myosin subfragment 1 to actin and substructure considerations.
Heat treatment of myosin subfragment 1 at 35 degrees C caused about 95% inactivation of the catalytic function but did not block its binding to actin. Heat-treated subfragment 1 showed specific, strong, and close to stoichiometric binding to actin. MgATP but not MgADP dissociated these complexes. However, in contrast to intact subfragment 1, the heat-treated protein did not polymerize G-actin and was not protected from trypsin by the binding to actin. Tryptic degradation of the 50K fragment abolished, or reduced greatly, the binding of heat-treated subfragment 1 to actin in solution but not on nitrocellulose overlays. These results are discussed in the context of subfragment 1 substructure.
Department of Chemistry and Biochemistry, University of California, Los Angeles 90024.
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Cheung
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Reisler
D000199:Actins / Q000032:analysis*; D001665:Binding Sites; D003101:Collodion; D006358:Hot Temperature; D015879:Myosin Subfragments; D009218:Myosins / Q000032:analysis*; D010446:Peptide Fragments / Q000032:analysis*; D011485:Protein Binding; D011489:Protein Denaturation; D014357:Trypsin
D000199:Actins; D015879:Myosin Subfragments; D010446:Peptide Fragments; D003101:Collodion; D014357:Trypsin; D009218:Myosins