1,3-Diethylurea-enhanced Mg-ATPase activity of skeletal muscle myosin with a converse effect on the sliding motility

Tetsuichi Wazawa, Shin Ichiro Yasui, Nobuyuki Morimoto, Makoto Suzuki

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We investigate the effects of urea and its derivatives on the ATPase activity and on the in vitro motility of chicken skeletal muscle actomyosin. Mg-ATPase rate of myosin subfragment-1 (S1) is increased by 4-fold by 0.3 M 1,3-diethylurea (DEU), but it is unaffected by urea, thiourea, and 1,3-dimethylurea at ≤ 1 M concentration. Thus, we further examine the effects of DEU in comparison to those of urea as reference. In in vitro motility assay, we find that in the presence of 0.3 M DEU, the sliding speeds of actin filaments driven by myosin and heavy meromyosin (HMM) are significantly decreased to 1/16 and 1/6.6, respectively, compared with the controls. However, the measurement of the actin-activated ATPase activity of HMM shows that the maximal rate, Vmax, is almost unchanged with DEU. Thus, the myosin-driven sliding motility of actin filaments is significantly impeded in the presence of 0.3 M DEU, whereas the cyclic interaction of myosin with F-actin occurs during the ATP turnover, the rate of which is close to that without DEU. In contrast to DEU, 0.3 M urea exhibits only modest effects on both actin-activated ATPase and sliding motility of actomyosin. Thus, DEU has the effect of uncoupling the sliding motility of actomyosin from its ATP turnover.

Original languageEnglish
Pages (from-to)2620-2629
Number of pages10
JournalBiochimica et Biophysica Acta - Proteins and Proteomics
Volume1834
Issue number12
DOIs
Publication statusPublished - 2013 Oct 11

Keywords

  • ATP hydrolysis
  • Actomyosin
  • Alkylurea derivative
  • Cosolvent effect
  • Mechanochemical coupling
  • Sliding motility

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biophysics
  • Biochemistry
  • Molecular Biology

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