Abstract
DNA is a flexible molecule, but the degree of its flexibility is subject to debate. The commonly-accepted persistence length of is inconsistent with recent studies on short-chain DNA that show much greater flexibility but do not probe its origin. We have performed x-ray and neutron small-angle scattering on a short DNA sequence containing a strong nucleosome positioning element and analyzed the results using a modified Kratky-Porod model to determine possible conformations. Our results support a hypothesis from Crick and Klug in 1975 that some DNA sequences in solution can have sharp kinks, potentially resolving the discrepancy. Our conclusions are supported by measurements on a radiation-damaged sample, where single-strand breaks lead to increased flexibility and by an analysis of data from another sequence, which does not have kinks, but where our method can detect a locally enhanced flexibility due to an AT domain.
- Received 30 March 2018
DOI:https://doi.org/10.1103/PhysRevE.98.042417
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