title: Effect of alpha-actinin on actin structure: viscosity studies.
abstract: The effect of ATP on ability of alpha-actinin to increase viscosity of F-actin was measured in three different solutions: 100 mM KCl; 100 mM KCl/l mM Mg2+; and Mg2+ alone at concentrations of 1-6 mM. When ATP and Mg2+ are added at equimolar ratios or at added [ATP] to added [Mg2+] greater than equimolar, alpha-actinin has no effect on F-actin viscosity in the absence of KCl. ATP decreases viscosity of alpha-actinin/F-actin mixtures by 20% even in the presence of KCl, evidently because ATP affects the alpha-actinin-F-actin interaction. Molar ratios of 1 alpha-actinin to 49 actins increase specific viscosity of F-actin approx. 2-fold at 37 degrees C in the presence of 1 mM ATP, so ATP does not prevent the alpha-actinin-F-actin interaction.
mesh_terms: D000185:Actinin / Q000494:pharmacology*; D000199:Actins / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology; D009124:Muscle Proteins / Q000494:pharmacology*; D013552:Swine; D014783:Viscosity
chemical_list: D000199:Actins; D009124:Muscle Proteins; D000185:Actinin; D000255:Adenosine Triphosphate; D008274:Magnesium