Cooperative structural change of actin filaments interacting with activated myosin motor domain, detected with copolymers of pyrene-labeled actin and acto-S1 chimera protein

Md Shahjahan P. Siddique, George Mogami, Takashi Miyazaki, Eisaku Katayama, Taro Q.P. Uyeda, Makoto Suzuki

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Acto-S1 chimera proteins CP24 and CP18 carry the entire actin sequence, inserted in loop 2 of the motor domain of Dictyostelium myosin II, and have MgATPase activity close to that of natural Dictyostelium actomyosin [M.S.P. Siddique, T. Miyazaki, E. Katayama, T.Q.P. Uyeda, M. Suzuki, Evidence against essential roles of subdomain 1 of actin in actomyosin sliding movements, Biochem. Biophys. Res. Commun. 332 (2005) 474-481]. Here, we examined and detected cooperative structural change of actin filaments accompanying interaction with myosin motor domain in the presence of ATP using copolymer filaments consisting of pyrene-labeled skeletal actin (SA) and either CP24 or CP18. Upon addition of ATP, the fluorescence intensity increased over the range from 380 to 480 nm using 365- nm excitation. The relative increases of fluorescence intensity at 390 nm were 14%, 46%, and 77% for the copolymer filaments with the CP24 to actin molar ratios of 0.0625, 0.143, and 0.333, respectively, and demonstrated a sigmoid behavior. Stoichiometric analysis indicates that each CP24 molecule appears to affect four actin molecules, on average, in SA-CP24 copolymers, and each CP18 molecule appears to affect three actin molecules in SA-CP18 copolymers.

Original languageEnglish
Pages (from-to)1185-1191
Number of pages7
JournalBiochemical and biophysical research communications
Volume337
Issue number4
DOIs
Publication statusPublished - 2005 Dec 2

Keywords

  • Actin filament
  • Acto-S1 chimera
  • Cooperative structural change
  • Dictyostelium
  • Fluorescence spectroscopy
  • Intermediate state
  • Motility function

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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