Influence of the bound nucleotide on the molecular dynamics of actin.
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.
Hegyi
G
G
Department of Biochemistry, Eötvös Loránd University, Budapest, Hungary.
Szilágyi
L
L
Belágyi
J
J
D000199:Actins / Q000378:metabolism*; D000227:Adenine Nucleotides / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D007700:Kinetics; D011485:Protein Binding; D011487:Protein Conformation
D000199:Actins; D000227:Adenine Nucleotides; C051606:8-bromoadenosine 5'-triphosphate; C056874:8-bromoadenosine 5'-diphosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate