| Reassessing the Mechanical Properties of DNA |
| Abstract ID | BIO-02 |
| Presenter | Rebecca
Fenn |
| Presentation Type | Poster
|
| Full Author List | R. . Mathew-Fenn (1) , R. Das (1) , P. B. Harbury (1)
|
| Affiliations | (1) Stanford University, Department of Biochemistry & Biophysics
|
| Category | Bio/Life Sciences |
| Abstract | DNA is thought to behave as a stiff elastic rod with respect to the ubiquitous mechanical deformations inherent to its biology. We have measured the mean and variance of end-to-end length for a series of DNA double helices in solution, using small-angle X-ray scattering interference between gold nanocrystal labels. The data rule out the conventional elastic rod model. Specifically, the variance in end-to-end length follows a quadratic dependence on the number of base pairs rather than the expected linear dependence. Absent applied tension, DNA is at least one order of magnitude softer than measured by single molecule stretching experiments. Our observations indicate that DNA stretching is cooperative over more than two turns of the DNA double helix, and support the idea of long range allosteric communication through DNA structure. |
| Footnotes | |
| Funding Acknowledgement | This work was supported by the National Institutes of Health (GM068126-01 to P.B.H.). We acknowledge additional funding from the National Institutes of Health (training grant fellowship to R.S.F., and support of SSRL), the National Science Foundation (graduate fellowship to R.D.), and the U.S. Department of Energy (Contract W-31-109-Eng-38 to APS and support of SSRL). |
