DNA force-extension curve under uniaxial stretching

Abstract

Single-molecule experiments indicate that a double-stranded DNA (ds‐DNA) increases in length if put under tension greater than 10 pN; beyond this point, its conformation can no longer be described using an inextensible worm-like chain model. For this purpose, a general sequence-dependent elastic model for tensions greater than 10 pN and for both single-stranded (ss) and ds‐DNA is proposed, and the effective elastic bending and torsional rigidities are determined from experiments to characterise their deformation. The key to this progress is that the bending and torsional deformations of the DNA backbones, the base-stacking interactions and the hydrogen bond force between the complementary base pairs are quantitatively considered in this model. Moreover, this simple elastic model can be used to globally fit to the abrupt B–S experimental transition data over a wide range of DNA molecule extensions. Based on this robust model, further study may be warranted on the mechanical response of ss- and ds‐DNA molecules.

Keywords:

• double-helical DNA structure
• mechanical properties
• single-molecule manipulation
• base-stacking interactions
• hydrogen bond forces

Notes

^1. Mailing Address: R2-6, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan. Tel./Fax: [phone].

^2. [email protected]

^3. [email protected]

^4. [email protected]

Additional information

Notes on contributors

Hamid Dalir

1. 1. Mailing Address: R2-6, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan. Tel./Fax: [phone].

Takasi Nisisako

2. 2. [email protected]

Yasuko Yanagida

3. 3. [email protected]

Takeshi Hatsuzawa

4. 4. [email protected]