Effect of alpha-actinin on actin structure. Release of bound nucleotide.
We have examined the alpha-actinin-F-actin interaction by measuring the effect of highly purified alpha-actinin on bound nucleotide exchange in F-actin. Exchange was followed by measuring the release of actin-bound [14C]ADP in the presence of ATP using an ultrafiltration technique. Alpha-Actinin increases by about 60 to 70% the rate of release of F-actin bound nucleotide when incubated for 1 h in the presence of 1 mM ATP/1 mM MgCl2/0.05 mM CaCl2/0.5 mM dithioerythritol/100 mM KCI/20 mM Tris-acetate, pH 7.5, at 37 degrees C. The ability of alpha-actinin to enhance nucleotide exchange was maximal when alpha-actinin was added at a level near 10% of actin present by weight (molar ratio of 1 alpha-actinin to 49 actin monomers). The potentiating effect of alpha-actinin on the nucleotide exchange rate of F-actin was not highly related to the Mg2+: ATP ratio present in the incubation mixture. Alpha-actinin also increased the rate of bound nucleotide exchange of f-actin was present in a reconstituted actomyosin suspension. The results are consistent with th possibility that one alpha-actinin can affect the structure of multiple actin monomers present in an actin filament.
D000185:Actinin / Q000494:pharmacology*; D000199:Actins / Q000378:metabolism*; D000205:Actomyosin / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D004305:Dose-Response Relationship, Drug; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D015636:Magnesium Chloride; D009124:Muscle Proteins / Q000494:pharmacology*; D009218:Myosins / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D013552:Swine
D000199:Actins; D009124:Muscle Proteins; D015636:Magnesium Chloride; D000185:Actinin; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000205:Actomyosin; D009218:Myosins; D008274:Magnesium