ADP‐ribosylation of actin causes increase in the rate of ATP exchange and inhibition of ATP hydrolysis

Abstract

ADP‐ribosylation of skeletal muscle actin by Clostridium perfringens iota toxin increased the rate of exchange of actin‐bound [γ‐32P]ATP by unlabelled ATP about twofold. Increased exchange rates were observed with ATP and ATP[γS], much less with ADP but not with AMP or NAD. ADP‐ribosylation of skeletal muscle actin reduced “basal” and Mg2+ (1 mM)‐induced ATP hydrolysis by about 80%. Similar inhibition of ATP hydrolysis was observed with liver actin ADP‐ribosylated by Clostridium botulinum C2 toxin. The data indicate that ADP‐ribosylation of actin at Arg‐177 largely affects the ATP‐binding and ATPase activity. Copyright © 1989, Wiley Blackwell. All rights reserved