Stretched and overwound DNA forms a Pauling-like structure with exposed bases.

@article{Allemand1998StretchedAO,
  title={Stretched and overwound DNA forms a Pauling-like structure with exposed bases.},
  author={J F Allemand and David Bensimon and Richard Lavery and Vincent Croquette},
  journal={Proceedings of the National Academy of Sciences of the United States of America},
  year={1998},
  volume={95 24},
  pages={14152-7}
}
We investigate structural transitions within a single stretched and supercoiled DNA molecule. With negative supercoiling, for a stretching force >0.3 pN, we observe the coexistence of B-DNA and denatured DNA from sigma approximately -0.015 down to sigma = -1. Surprisingly, for positively supercoiled DNA (sigma > +0.037) stretched by 3 pN, we observe a… CONTINUE READING