Affinity of myosin S-1 for F-actin, measured by time-resolved fluorescence anisotropy.
AUTOR(ES)
Highsmith, S
RESUMO
The association constant for myosin subfragment-1 (S-1) and actin was measured, using a new application of fluorescence depolarization which capitalizes on the fact that S-1 has high rotational mobility while F-actin does not. Uncoupling of the time dependences of the anisotropy decay and the association/dissociation phenomena allowed the experimentally determined anisotropy decay curve to be fitted by a sum of two terms weighted by the mole fractions of the free and bound S-1. At 4 degrees C, ionic strength 0.16 M, and pH 7.0, the association constant Ka is (1.73 +/- 0.35) X 10(6) M-1 at infinite dilution. This makes the -deltaG degrees of binding of F-actin to S-1 similar to the -deltaG degrees of binding of ATP to S-1, and the possible physiological relevance of the similarity to muscle contraction is discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=335854Documentos Relacionados
- Affinity of myosin S-1 for F-actin, measured by time-resolved fluorescence anisotropy
- Rotational diffusion of cell surface components by time-resolved phosphorescence anisotropy.
- Time-resolved fluorescence anisotropy of fluorescent-labeled lysophospholipid and taurodeoxycholate aggregates.
- Detection of membrane packing defects by time-resolved fluorescence depolarization.
- DNA binding induces dissociation of the multimeric form of HIV-1 integrase: A time-resolved fluorescence anisotropy study
