Antibody against the amino terminus of alpha-actin inhibits actomyosin interactions in the presence of ATP

J Mol Biol. 1989 Jun 20;207(4):833-6. doi: 10.1016/0022-2836(89)90249-0.

Abstract

Actomyosin interactions in the presence of ATP were examined by using site-specific antibodies directed against the first seven N-terminal residues on skeletal alpha-actin. Fab fragments of these antibodies (S alpha N Fab) inhibited effectively the actin-activated ATPase of myosin subfragment 1 (S-1) at both 5 and 25 degrees C. Binding experiments carried out in the presence of ATP at 5 degrees C revealed that the catalytic inhibition was related to the inhibition of S-1 binding to actin by Fab. At equimolar ratios of Fab to actin, the binding of S-1 to actin and the activated ATPase were inhibited by 75 and 82%, respectively. These results, when contrasted with the small effect of Fab on rigor actomyosin binding, suggest ATP-induced changes at the interface of actin and myosin.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / immunology*
  • Actomyosin / metabolism*
  • Adenosine Triphosphate / metabolism*
  • Animals
  • Binding Sites
  • Immunoglobulin Fragments / immunology*
  • Muscles / metabolism

Substances

  • Actins
  • Immunoglobulin Fragments
  • Adenosine Triphosphate
  • Actomyosin