17 June 1993 Rotational dynamics of short DNAs
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Proceedings Volume 1922, Laser Study of Macroscopic Biosystems; (1993) https://doi.org/10.1117/12.146160
Event: Laser Spectroscopy of Biomolecules: 4th International Conference on Laser Applications in Life Sciences, 1992, Jyvaskyla, Finland
The fluorescence polarization anisotropies of ethidium intercalated in duplex DNAs containing 12 to 60 bp were measured and analyzed using a theory of deformable rods to obtain their hydrodynamic radii (RH). The apparent RH is 10.0 +/- 0.2 angstroms for 12 and 24 bp, but increases to 11.5 - 12.0 angstroms between 40 and 60 bp. This variation in RH is attributed to the presence of slowly relaxing bends in the DNA. Consequently, the static equilibrium persistence length must be much smaller than the dynamic persistence length (Pd) defined by the dynamic (instantaneous) bending rigidity. We estimate that Pd > 1000 angstroms. RH of a 48 bp duplex DNA is largely independent of NaCl concentration, which suggests that interionic forces do not much affect the rotational friction. However, RH depends significantly on the concentrations of other ions, especially Mg2+ and Mn2+, which are believed to affect the hydration of DNA.
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Bryant S. Fujimoto, Julia M. Miller, Susan Ribeiro, J. Michael Schurr, "Rotational dynamics of short DNAs", Proc. SPIE 1922, Laser Study of Macroscopic Biosystems, (17 June 1993); doi: 10.1117/12.146160; https://doi.org/10.1117/12.146160

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