in 10 mM Na+ buffer ~53nm: in 80 mM Na+ buffer ~15nm nm
||Wang MD et al., Stretching DNA with optical tweezers. Biophys J. 1997 Mar72(3):1335-46. p.1335 right column bottom paragraphPubMed ID9138579
||Bustamante, C., J. F. Marko, E. D. Siggia, and S. Smith. 1994. Entropic elasticity of λ-phage DNA. Science. 265: 1599-1600. AND Cluzel, P., A. Lebrun, C. Heller, R. Lavery, J. L. Viovy, D. Chastenay, D., and F. Caron. 1996. DNA: an extensible molecule. Science. 271: 792-794.PubMed ID8079175, 8628993
||P.1335 right column bottom paragraph: "The extensibility of DNA has been measured using forces applied by magnets or fluid flow (Smith et al., 1992), and more recently with optical traps (Smith et al., 1996) or glass microneedles (primary source Cluzel et al., 1996). To an excellent approximation, single molecules of DNA behave like ideal, entropic springs for low-to-moderate extension beyond their rest length. The elastic behavior of such springs is characterized by a polymer persistence length, Lp. Data fits to the low-force regime of the F-x curve gave persistence lengths of ~53 nm (in 10 mM Na+ buffer primary source Bustamante et al., 1994)
or ~15 nm (in 80 mM Na+ buffer, primary source Cluzel et al., 1996)."