Improving signal/noise resolution in single-molecule experiments using molecular constructs with short handles

N. Forns, S. De Lorenzo, M. Manosas, K. Hayashi, J. M. Huguet, F. Ritort

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

We investigate unfolding/folding force kinetics in DNA hairpins exhibiting two and three states with newly designed short dsDNA handles (29 bp) using optical tweezers. We show how the higher stiffness of the molecular setup moderately enhances the signal/noise ratio (SNR) in hopping experiments as compared to conventional long-handled constructs (≅700 bp). The shorter construct results in a signal of higher SNR and slower folding/unfolding kinetics, thereby facilitating the detection of otherwise fast structural transitions. A novel analysis, as far as we are aware, of the elastic properties of the molecular setup, based on high-bandwidth measurements of force fluctuations along the folded branch, reveals that the highest SNR that can be achieved with short handles is potentially limited by the marked reduction of the effective persistence length and stretch modulus of the short linker complex.

Original languageEnglish
Pages (from-to)1765-1774
Number of pages10
JournalBiophysical Journal
Volume100
Issue number7
DOIs
Publication statusPublished - 2011 Apr 6
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics

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