Dynamic measurement of single protein's mechanical properties

Keita Mitsui, Ken Nakajima, Hideo Arakawa, Masahiko Hara, Atsushi Ikai

    Research output: Contribution to journalArticlepeer-review

    56 Citations (Scopus)


    Dimerized (tandemly repeated) protein was constructed, and the stretching force during the unfolding of the single protein molecule was measured using an atomic force microscope. In quasistatic measurements using normal force-distance curve measurements, each monomer unit was unfolded step by step. To elucidate the conformational state at each extension length, we measured the relax-stress response of the protein using short stroke sinusoidal movements of the sample stage. This allowed us to investigate the dynamic response of the protein repeatedly without full stretching or rupturing. Although the protein molecule responded in-phase to the applied movement in most cases, we found a novel out-of-phase response around the stretching length where the second monomer unit unfolded. Applying the spring constant measured in the quasistatic experiment, the out-of-phase response was reproduced in the simple calculation, which suggested the folding and the unfolding at the second monomer unit were taking place repeatedly during the relax-stress response measurement. (C) 2000 Academic Press.

    Original languageEnglish
    Pages (from-to)55-63
    Number of pages9
    JournalBiochemical and biophysical research communications
    Issue number1
    Publication statusPublished - 2000 May 27

    ASJC Scopus subject areas

    • Biophysics
    • Biochemistry
    • Molecular Biology
    • Cell Biology


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