Conformational and dynamic differences between actin filaments polymerized from ATP- or ADP-actin monomers.
Conformational and dynamic properties of actin filaments polymerized from ATP- or ADP-actin monomers were compared by using fluorescence spectroscopic methods. The fluorescence intensity of IAEDANS attached to the Cys(374) residue of actin was smaller in filaments from ADP-actin than in filaments from ATP-actin monomers, which reflected a nucleotide-induced conformational difference in subdomain 1 of the monomer. Radial coordinate calculations revealed that this conformational difference did not modify the distance of Cys(374) from the longitudinal filament axis. Temperature-dependent fluorescence resonance energy transfer measurements between donor and acceptor molecules on Cys(374) of neighboring actin protomers revealed that the inter-monomer flexibility of filaments assembled from ADP-actin monomers were substantially greater than the one of filaments from ATP-actin monomers. Flexibility was reduced by phalloidin in both types of filaments.
Nyitrai
M
M
Research Group for Fluorescence Spectroscopy, University of Pécs, Pécs, Hungary.
Hild
G
G
Hartvig
N
N
Belágyi
J
J
Somogyi
B
B
D000199:Actins / Q000737:chemistry*; D000244:Adenosine Diphosphate / Q000737:chemistry*; D000255:Adenosine Triphosphate / Q000737:chemistry*; D000818:Animals; D011108:Polymers / Q000737:chemistry; D011487:Protein Conformation; D011817:Rabbits; D013696:Temperature
D000199:Actins; D011108:Polymers; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate