ADP Binding Induces an Asymmetry between the Heads of Unphosphorylated Myosin
| Autor: | Kathleen M. Trybus, Christine E. M. Berger, Michael A. Geeves, Stefan Heizmann, Patricia M. Fagnant |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
macromolecular substances
Myosins Biology Immunoglobulin light chain Models Biological Biochemistry Motor protein Adenosine Triphosphate Myosin Animals Nucleotide Phosphorylation Molecular Biology Actin chemistry.chemical_classification Heavy meromyosin Myosin Subfragments Cell Biology Actins Adenosine Diphosphate Kinetics chemistry Biophysics ADP binding Protein Binding |
| Zdroj: | Journal of Biological Chemistry. 276:23240-23245 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m100524200 |
| Popis: | Light chain phosphorylation is the key event that regulates smooth and non-muscle myosin II ATPase activity. Here we show that both heads of smooth muscle heavy meromyosin (HMM) bind tightly to actin in the absence of nucleotide, irrespective of the state of light chain phosphorylation. In striking contrast, only one of the two heads of unphosphorylated HMM binds to actin in the presence of ADP, and the heads have different affinities for ADP. This asymmetry suggests that phosphorylation alters the mechanical coupling between the heads of HMM. A model that incorporates strain between the two heads is proposed to explain the data, which have implications for how one head of a motor protein can gate the response of the other. |
| Databáze: | OpenAIRE |
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