Mechanical measurements of single actomyosin motor force

H. Miyata*, H. Yoshikawa, H. Hakozaki, N. Suzuki, T. Furuno, A. Ikegami, K. Kinosita, T. Nishizaka, S. Ishiwata, P. Driezen, A. Mehta

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

To elucidate the mechanism of force generation by actomyosin motor, a measuring system was constructed, in which an in vitro motility assay was combined with an optical trapping technique. An actin filament of several μm long was attached to a gelsolin-coated polystyrene bead, and was allowed to interact with a small number (~1/1-μm actin filament) of rabbit skeletal heavy meromyosin (an active subfragment of myosin) molecules bound to a nitrocellulose-coated coverglass. The bead position was determined at 33-ms intervals. We measured the force generation event at relatively low (100-400 nM) ATP concentration so that the occurrence of individual force generation events could be detected with our time resolution. The actin-bound bead held in the optical trap moved in a stepwise manner in the direction of the actin filament only in the presence of ATP. At the trap strength of 0.3 pN/nm, the maximum size of the step was 11 nm, and the maximum force associated with the movement was 3.3 pN.

Original languageEnglish
JournalBiophysical Journal
Volume68
Issue number4 SUPPL.
Publication statusPublished - 1995
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics

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