Formation and properties of smooth muscle myosin 20-kDa light chain-skeletal muscle myosin hybrids and photocrosslinking from the maleimidylbenzophenone-labeled light chain to the heavy chain

Arch Biochem Biophys. 1991 Aug 1;288(2):584-90. doi: 10.1016/0003-9861(91)90240-j.

Abstract

Experimental conditions which permit the exchange of smooth muscle 20-kDa light chain into skeletal muscle myosin are described. The hybridization does not result in the regulation of actin-activated ATPase activity of the hybrid myosin by smooth light chain phosphorylation. Further, the KCl dependence of the Mg-ATPase activity of the hybrid was similar to that of skeletal muscle myosin. The dephosphorylation of the smooth light chain in the hybrid did not induce a conformational change in the hybrid from the 6 S to the 10 S state, thereby indicating that the conformational transition is dependent also on the nature of the heavy chain subunit. Exchange of the smooth light chain premodified at its Cys-108 by photolabile 4-(N-maleimido)benzophenone and photolysis resulted in crosslinking to the heavy chain subunit. Immunopeptide mapping using a monoclonal antibody against residues 1-23 at the N-terminus of the skeletal muscle myosin heavy chain identified the location of the photocrosslinking site to be beyond 92 kDa away from the N-terminus.

Publication types

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

MeSH terms

  • Actins / metabolism
  • Animals
  • Benzophenones / pharmacology*
  • Ca(2+) Mg(2+)-ATPase / metabolism
  • Cross-Linking Reagents / pharmacology
  • Kinetics
  • Macromolecular Substances
  • Maleimides*
  • Molecular Weight
  • Muscles / metabolism
  • Myosins / metabolism*
  • Peptide Mapping
  • Photolysis
  • Potassium Chloride / pharmacology
  • Protein Conformation
  • Protein Multimerization
  • Rabbits

Substances

  • Actins
  • Benzophenones
  • Cross-Linking Reagents
  • Macromolecular Substances
  • Maleimides
  • Potassium Chloride
  • benzophenone-4-maleimide
  • Ca(2+) Mg(2+)-ATPase
  • Myosins