Reversible unfolding of single RNA molecules by mechanical force.
Here we use mechanical force to induce the unfolding and refolding of single RNA molecules: a simple RNA hairpin, a molecule containing a three-helix junction, and the P5abc domain of the Tetrahymena thermophila ribozyme. All three molecules (P5abc only in the absence of Mg2+) can be mechanically unfolded at equilibrium, and when kept at constant force within a critical force range, are bi-stable and hop between folded and unfolded states. We determine the force-dependent equilibrium constants for folding/unfolding these single RNA molecules and the positions of their transition states along the reaction coordinate.
Liphardt
J
J
Department of Chemistry, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA. jliphard@alice.berkeley.gov
Onoa
B
B
Smith
S B
SB
Tinoco
I
I
Bustamante
C
C
D000818:Animals; D001483:Base Sequence; D004492:Edetic Acid; D007700:Kinetics; D008274:Magnesium; D008863:Microspheres; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011137:Polystyrenes; D012313:RNA / Q000737:chemistry*; D020871:RNA Stability; D016337:RNA, Catalytic / Q000737:chemistry*; D013314:Stress, Mechanical; D016808:Tetrahymena thermophila; D013816:Thermodynamics
D011137:Polystyrenes; D016337:RNA, Catalytic; D012313:RNA; D004492:Edetic Acid; D008274:Magnesium