Abstract
Tethered particle motion (TPM) has become an important tool for single-molecule studies of biomolecules; however, concerns remain that the method may alter the dynamics of the biophysical process under study. We investigate the effect of the attached microsphere on an illustrative biological example: the formation and breakdown of protein-mediated DNA loops in the lac repressor system. By comparing data from a conventional TPM experiment with 800 nm polystyrene beads and dark-field TPM using 50 nm Au nanoparticles, we found that the lifetimes of the looped and unlooped states are only weakly modified, less than two-fold, by the presence of the large bead. This is consistent with our expectation of weak excluded-volume effects and hydrodynamic surface interactions from the cover glass and microsphere.
Original language | English |
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Pages (from-to) | 144-150 |
Number of pages | 7 |
Journal | Biopolymers |
Volume | 95 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2011 |
Keywords
- DNA looping
- TPM
- single molecule techniques