A cross section of the thin filament based on an actin filament model by Oda et al. [45].

<p>The acceptor labeling sties used in previous FRET studies (Gln41, Lys61, Cys374 and the bound nucleotide) are shown as red balls, and are located in the outer domain of actin filament. In this study, acceptors are labeled on phalloidin (shown as a blue ball on the inner domain of actin filament), Cys374 on actin, or Cys190 on cTm. The donor probe labeled on cTnI is shown as a green ball.