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Characterization of the Cation and Temperature Dependence of DNA Quadruplex Hydrogen Bond Properties Using High-Resolution NMR

Dingley, A. J. and Peterson, R. D. and Grzesiek, S. and Feigon, J.. (2005) Characterization of the Cation and Temperature Dependence of DNA Quadruplex Hydrogen Bond Properties Using High-Resolution NMR. Journal of the American Chemical Society, Vol. 127, H. 41. pp. 14466-14472.

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Official URL: http://edoc.unibas.ch/dok/A5258778

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Abstract

Variations in the hydrogen bond network of the Oxy-1.5 DNA guanine quadruplex have been monitored by trans-H-bond scalar couplings, (h2)J(N2N7), for Na(+)-, K(+)-, and NH(4)(+)-bound forms over a temperature range from 5 to 55 degrees C. The variations in (h2)J(N2N7) couplings exhibit an overall trend of Na(+) < K(+) < NH(4)(+) and correlate with the different cation positions and N2-H2...N7 H-bond lengths in the respective structures. A global weakening of the (h2)J(N2N7) couplings with increasing temperature for the three DNA quadruplex species is accompanied by a global increase of the acceptor (15)N7 chemical shifts. Above 35 degrees C, spectral heterogeneity indicates thermal denaturation for the Na(+)-bound form, whereas spectral homogeneity persists up to 55 degrees C for the K(+)- and NH(4)(+)-coordinated forms. The average relative change of the (h2)J(N2N7) couplings amounts to approximately 0.8 x 10(-)(3)/K and is thus considerably smaller than respective values reported for nucleic acid duplexes. The significantly higher thermal stability of H-bond geometries in the DNA quadruplexes can be rationalized by their cation coordination of the G-quartets and the extensive H-bond network between the four strands. A detailed analysis of individual (h2)J(N2N7) couplings reveals that the 5' strand end, comprising base pairs G1-G9 and G4-G1, is the most thermolabile region of the DNA quadruplex in all three cation-bound forms.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Structural Biology & Biophysics > Structural Biology (Grzesiek)
UniBasel Contributors:Grzesiek, Stephan
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
ISSN:0002-7863
Note:Publication type according to Uni Basel Research Database: Journal article
Last Modified:22 Mar 2012 14:20
Deposited On:22 Mar 2012 13:21

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