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. 1999 Jul;77(1):114–122. doi: 10.1016/S0006-3495(99)76876-1

The iso-competition point for counterion competition binding to DNA: calculated multivalent versus monovalent cation binding equivalence.

A Z Li 1, K A Marx 1
PMCID: PMC1300316  PMID: 10388744

Abstract

In this paper we introduce an important parameter called the iso-competition point (ICP), to characterize the competition binding to DNA in a two-cation-species system. By imposing the condition of charge neutralization fraction equivalence theta1 = ZthetaZ upon the two simultaneous equations in Manning's counterion condensation theory, the ICPs can be calculated. Each ICP, which refers to a particular multivalent concentration where the charge fraction on DNA neutralized from monovalent cations equals that from the multivalent cations, corresponds to a specific ionic strength condition. At fixed ionic strength, the total DNA charge neutralization fractions thetaICP are equal, no matter whether the higher valence cation is divalent, trivalent, or tetravalent. The ionic strength effect on ICP can be expressed by a semiquantitative equation as ICPZa/ICPZb = (Ia/Ib)Z, where Ia, Ib refers to the instance of ionic strengths and Z indicates the valence. The ICP can be used to interpret and characterize the ionic strength, valence, and DNA length effects on the counterion competition binding in a two-species system. Data from our previous investigations involving binding of Mg2+, Ca2+, and Co(NH3)63+ to lambda-DNA-HindIII fragments ranging from 2.0 to 23.1 kbp was used to investigate the applicability of ICP to describe counterion binding. It will be shown that the ICP parameter presents a prospective picture of the counterion competition binding to polyelectrolyte DNA under a specific ion environment condition.

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Selected References

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  1. Allison S. A., Herr J. C., Schurr J. M. Structure of viral phi 29 DNA condensed by simple triamines: a light-scattering and electron-microscopy study. Biopolymers. 1981 Mar;20(3):469–488. doi: 10.1002/bip.1981.360200305. [DOI] [PubMed] [Google Scholar]
  2. Arscott P. G., Li A. Z., Bloomfield V. A. Condensation of DNA by trivalent cations. 1. Effects of DNA length and topology on the size and shape of condensed particles. Biopolymers. 1990;30(5-6):619–630. doi: 10.1002/bip.360300514. [DOI] [PubMed] [Google Scholar]
  3. Bloomfield V. A. Condensation of DNA by multivalent cations: considerations on mechanism. Biopolymers. 1991 Nov;31(13):1471–1481. doi: 10.1002/bip.360311305. [DOI] [PubMed] [Google Scholar]
  4. Granot J., Kearns D. R. Interactions of DNA with divalent metal ions. III. Extent of metal binding: experiment and theory. Biopolymers. 1982 Jan;21(1):219–232. doi: 10.1002/bip.360210117. [DOI] [PubMed] [Google Scholar]
  5. Holzwarth G., Platt K. J., McKee C. B., Whitcomb R. W., Crater G. D. The acceleration of linear DNA during pulsed-field gel electrophoresis. Biopolymers. 1989 Jun;28(6):1043–1058. doi: 10.1002/bip.360280603. [DOI] [PubMed] [Google Scholar]
  6. Labarbe R., Flock S., Maus C., Houssier C. Polyelectrolyte counterion condensation theory explains differential scanning calorimetry studies of salt-induced condensation of chicken erythrocyte chromatin. Biochemistry. 1996 Mar 12;35(10):3319–3327. doi: 10.1021/bi951636j. [DOI] [PubMed] [Google Scholar]
  7. Langlais M., Tajmir-Riahi H. A., Savoie R. Raman spectroscopic study of the effects of Ca2+, Mg2+, Zn2+, and Cd2+ ions on calf thymus DNA: binding sites and conformational changes. Biopolymers. 1990;30(7-8):743–752. doi: 10.1002/bip.360300709. [DOI] [PubMed] [Google Scholar]
  8. Li A. Z., Huang H., Re X., Qi L. J., Marx K. A. A gel electrophoresis study of the competitive effects of monovalent counterion on the extent of divalent counterions binding to DNA. Biophys J. 1998 Feb;74(2 Pt 1):964–973. doi: 10.1016/S0006-3495(98)74019-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Li A. Z., Qi L. J., Shih H. H., Marx K. A. Trivalent counterion condensation on DNA measured by pulse gel electrophoresis. Biopolymers. 1996 Mar;38(3):367–376. doi: 10.1002/(sici)1097-0282(199603)38:3<367::aid-bip9>3.0.co;2-s. [DOI] [PubMed] [Google Scholar]
  10. Ma C., Bloomfield V. A. Gel electrophoresis measurement of counterion condensation on DNA. Biopolymers. 1995 Feb;35(2):211–216. doi: 10.1002/bip.360350209. [DOI] [PubMed] [Google Scholar]
  11. Manning G. S. Limiting laws and counterion condensation in polyelectrolyte solutions. IV. The approach to the limit and the extraordinary stability of the charge fraction. Biophys Chem. 1977 Sep;7(2):95–102. doi: 10.1016/0301-4622(77)80002-1. [DOI] [PubMed] [Google Scholar]
  12. Manning G. S. The molecular theory of polyelectrolyte solutions with applications to the electrostatic properties of polynucleotides. Q Rev Biophys. 1978 May;11(2):179–246. doi: 10.1017/s0033583500002031. [DOI] [PubMed] [Google Scholar]
  13. Marx K. A., Reynolds T. C. Micrococcal nuclease digestion study of spermidine-condensed DNA. Int J Biol Macromol. 1989 Aug;11(4):241–248. doi: 10.1016/0141-8130(89)90076-7. [DOI] [PubMed] [Google Scholar]
  14. Marx K. A., Reynolds T. C. Spermidine-condensed phi X174 DNA cleavage by micrococcal nuclease: torus cleavage model and evidence for unidirectional circumferential DNA wrapping. Proc Natl Acad Sci U S A. 1982 Nov;79(21):6484–6488. doi: 10.1073/pnas.79.21.6484. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Marx K. A., Ruben G. C. A study of phi X-174 DNA torus and lambda DNA torus tertiary structure and the implications for DNA self-assembly. J Biomol Struct Dyn. 1986 Aug;4(1):23–39. doi: 10.1080/07391102.1986.10507644. [DOI] [PubMed] [Google Scholar]
  16. Marx K. A., Ruben G. C. Evidence for hydrated spermidine-calf thymus DNA toruses organized by circumferential DNA wrapping. Nucleic Acids Res. 1983 Mar 25;11(6):1839–1854. doi: 10.1093/nar/11.6.1839. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Plum G. E., Arscott P. G., Bloomfield V. A. Condensation of DNA by trivalent cations. 2. Effects of cation structure. Biopolymers. 1990;30(5-6):631–643. doi: 10.1002/bip.360300515. [DOI] [PubMed] [Google Scholar]
  18. Widom J., Baldwin R. L. Cation-induced toroidal condensation of DNA studies with Co3+(NH3)6. J Mol Biol. 1980 Dec 25;144(4):431–453. doi: 10.1016/0022-2836(80)90330-7. [DOI] [PubMed] [Google Scholar]
  19. Wilson R. W., Bloomfield V. A. Counterion-induced condesation of deoxyribonucleic acid. a light-scattering study. Biochemistry. 1979 May 29;18(11):2192–2196. doi: 10.1021/bi00578a009. [DOI] [PubMed] [Google Scholar]

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