Ammonium ion at low concentration stabilizes the G-quadruplex formation by telomeric sequence

Nagesh, Narayana ; Chatterji, Dipankar (1995) Ammonium ion at low concentration stabilizes the G-quadruplex formation by telomeric sequence Journal of Biochemical and Biophysical Methods, 30 (1). pp. 1-8. ISSN 0165-022X

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/016502...

Abstract

A synthetic analog of telomeric DNA, d(T6G16) or d(G4T2G4T2G4T2G4) was found to form G-quadruplex structure in NH4-ion environments as low as 1 mM. Other counter ions like K(I) or Sr(II) known to have a stabilizing effect on G-tetrad require much higher concentrations. The multiconformational form of G-tetrad could be identified in NH4(I) upon heating the sample up to 100° C. Circular dichroism spectral studies indicated that on thermally treating the complex NH4(I) ion helps in intramolecular G-tetrad formation over intermolecular association. However the G-tetrad structure formed in NH4(I) was found to be unstable in the presence of intercalator Actinomycin D or Tb(III) ion. It appears that the ionic radius of NH4(I) influences tight fitting of this ion inside the cavity of the tetrad. The stability of G-tetrad in the presence of very low concentration of NH4(I) may have potential applications in future.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:G-tetrad; NH4(I); Stability; Thermal Treatment; CD; Fluorescence
ID Code:6302
Deposited On:20 Oct 2010 11:13
Last Modified:08 Feb 2011 06:29

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