Salt dependence of the persistence length of DNA

Range Table - link Å
Organism Unspecified
Reference Record MT Jr et al., Double helical DNA: conformations, physical properties, and interactions with ligands. Annu Rev Biochem. 1981 50 :997-1024. p.1008 table 2PubMed ID7023371
Primary Source [86] Kam Z, Borochov N, Eisenberg H. Dependence of laser light scattering of DNA on NaCl concentration. Biopolymers. 1981 Dec20(12):2671-90. [87] Hearst, J. E., Schmid, C. W., Rinehart, F. P. 1968. Macromolecules 1:491-94 [91] Harrington, R E. 1978. Biopolymers 17: 919-36 [93] Frontali C et al., An absolute method for the determination of the persistence length of native DNA from electron micrographs. Biopolymers. 1979 Jun18(6):1353-73.PubMed ID7034800, 465647
Comments P.1007 bottom paragraph: "Several studies of the salt dependence of the persistence length exist. The results are summarized in Table 2. All of the available data agree that as the salt concentration is lowered, a [persistence length] increases. A large dependence of the persistence length upon salt concentration was obtained from a statistical analysis of local curvature of T2 DNA fragments examined by electron microscopy (primary source 93). Fragments were adsorbed on to a cytochrome c coated grid from solutions containing ammonium acetate. Evaluation of these results is impeded by lack of knowledge of the effect of salt upon the cytochrome c-DNA interaction. Moreover, the effects of excluded volume on the conformation of these fragments, stated to be a few microns in length and therefore possibly subject to such constraints in solution, were not taken into account (ref 93a). Harrington (primary source 91) combined flow birefringence and intrinsic viscosity data on T2 DNA to obtain a steep dependence of a on salt when the experimental data was calibrated with a = 660 Å at 0.2 M NaCl. A recent light-scattering study on the linear form of the ColE1 plasmid (M = 4.4X10^6 [g/mol]) (primary source 86) determined a with and without an excluded volume correction (see Table 2). When excluded volume is considered, a = 370 Å at 0.2 M NaCI, and the increase in a with decreasing salt is reduced. Recalibration of Harrington's data (R. E. Harrington, personal communication) using this value of a results in a less dramatic salt dependence that is in reasonable agreement with the light-scattering data, as well as with that obtained in an earlier analysis (primary source 87) of salt dependent hydrodynamic data." See notes beneath table
Entered by Uri M
ID 112631