Key result
Replacement of the bound nucleotide by Br8ATP or Br8ADP in actin significantly increased the rotational correlation time of the spin probe and decreased myosin S1 ATPase activation.
The bound nucleotide in actin significantly influences its molecular dynamics and interaction with myosin S1 ATPase.
Should not change practice; leaves open nucleotide effects on actin-myosin interactions in humans.
Rotational dynamics of actin spin-labelled with maleimide probes at the reactive thiol Cys-374 were studied. Replacement of the bound nucleotide by Br8ATP in G-actin and Br8ADP in F-actin causes significant increase of the rotational correlation time of the spin probe, indicating reduced motion in both G and F-actin. The orientation dependence of the electron paramagnetic resonance spectra in oriented F-actin filaments revealed an altered molecular order of the probe when the nucleotide was a Br-substituted one. The bound nucleotide affects the myosin S1 ATPase activation by actin; both Vmax and K(actin) decreased significantly when the bound nucleotide of actin was Br8ADP.
No takes yet. Share an insight, caveat, or question.
Hegyi et al. (1988) studied this question. Br8ATP and Br8ADP substitution vs. Unsubstituted bound nucleotide was evaluated on Rotational correlation time, molecular order, and myosin S1 ATPase activation. Replacement of the bound nucleotide by Br8ATP or Br8ADP in actin significantly increased the rotational correlation time of the spin probe and decreased myosin S1 ATPase activation.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: