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Origin of overstretching transitions in single-stranded nucleic acids

Publication ,  Journal Article
Scholl, ZN; Rabbi, M; Lee, D; Manson, L; S-Gracz, H; Marszalek, PE
Published in: Physical review letters
November 1, 2013

We combined single-molecule force spectroscopy with nuclear magnetic resonance measurements and molecular mechanics simulations to examine overstretching transitions in single-stranded nucleic acids. In single-stranded DNA and single-stranded RNA there is a low-force transition that involves unwinding of the helical structure, along with base unstacking. We determined that the high-force transition that occurs in polydeoxyadenylic acid single-stranded DNA is caused by the cooperative forced flipping of the dihedral angle formed between four atoms, O5'-C5'-C4'-C3' (γ torsion), in the nucleic acid backbone within the canonical B-type helix. The γ torsion also flips under force in A-type helices, where the helix is shorter and wider as compared to the B-type helix, but this transition is less cooperative than in the B type and does not generate a high-force plateau in the force spectrums of A-type helices. We find that a similar high-force transition can be induced in polyadenylic acid single-stranded RNA by urea, presumably due to disrupting the intramolecular hydrogen bonding in the backbone. We hypothesize that a pronounced high-force transition observed for B-type helices of double stranded DNA also involves a cooperative flip of the γ torsion. These observations suggest new fundamental relationships between the canonical structures of single-and double-stranded DNA and the mechanism of their molecular elasticity.

Duke Scholars

Published In

Physical review letters

EISSN

1079-7114

Publication Date

November 1, 2013

Volume

111

Issue

18

Start / End Page

188302

Related Subject Headings

  • General Physics
  • 09 Engineering
  • 02 Physical Sciences
  • 01 Mathematical Sciences
 

Citation

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Scholl, Z. N., Rabbi, M., Lee, D., Manson, L., S-Gracz, H., & Marszalek, P. E. (2013). Origin of overstretching transitions in single-stranded nucleic acids. Physical Review Letters, 111(18), 188302.
Scholl, Z. N., M. Rabbi, D. Lee, L. Manson, H. S-Gracz, and P. E. Marszalek. “Origin of overstretching transitions in single-stranded nucleic acids.” Physical Review Letters 111, no. 18 (November 1, 2013): 188302.
Scholl ZN, Rabbi M, Lee D, Manson L, S-Gracz H, Marszalek PE. Origin of overstretching transitions in single-stranded nucleic acids. Physical review letters. 2013 Nov 1;111(18):188302.
Scholl, Z. N., et al. “Origin of overstretching transitions in single-stranded nucleic acids.” Physical Review Letters, vol. 111, no. 18, Nov. 2013, p. 188302.
Scholl ZN, Rabbi M, Lee D, Manson L, S-Gracz H, Marszalek PE. Origin of overstretching transitions in single-stranded nucleic acids. Physical review letters. 2013 Nov 1;111(18):188302.

Published In

Physical review letters

EISSN

1079-7114

Publication Date

November 1, 2013

Volume

111

Issue

18

Start / End Page

188302

Related Subject Headings

  • General Physics
  • 09 Engineering
  • 02 Physical Sciences
  • 01 Mathematical Sciences