The techniques of the previous article are here applied to the case for which the solution contains, in addition to excess uni-univalent salt, one equivalent of divalent counterions per mole nucleotide. In agreement with the melting temperature measurements of Dove and Davidson for Mg++, it is predi
The application of polyelectrolyte limiting laws to the helix–coil transition of DNA. VI. The numerical value of the axial phosphate spacing for the coil form
✍ Scribed by Gerald S. Manning
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1976
- Tongue
- English
- Weight
- 391 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
Abstract
It is concluded on the basis of comparison of polyelectrolyte theory with published data that the mean phosphate spacing b along the contour axis of an unfolded polynucleotide single strand is in the range 3–4 Å (polyelectrolyte parameter ξ ≈ 2), regardless of temperature, base composition, or extent of stacking. This result is consistent with the low‐angle X‐ray scattering measurements of Gulik, Inoue, and Luzzati on poly(C). No conclusion may be drawn from this value of b concerning the structure of the chain skeleton or the spatial arrangement of the bases other than that the chain is far from an all‐trans local conformation (for which b would be about 6–7 Å, the length of a nucleotide unit). The structural implications, or lack thereof, are discussed in detail in the following paper.
📜 SIMILAR VOLUMES
The interaction of counterions with a suitably long, charged oligomer appears susceptible to treatment in the context of polyelectrolyte theory by the introduction of an end-effect parameter that reflects the reduced association of counterions with the terminal regions of the oligo-ion. Use of a phy
Omitted from the Introduction of this paper was the statement that the relationship that we propose between the end effect parameter (end and the reduced density (, where f is a proportionality constant, is an assumption that was motivated by the agreement with experimental data that its use provid