Characterization of the zinc-induced structural transition to *H-DNA at a d(GA·CT)22 sequence

Beltrán, R., Martínez-Balbás, A., Bernués, J., Bowater, R. and Azorín, F. (1993) Characterization of the zinc-induced structural transition to *H-DNA at a d(GA·CT)22 sequence. Journal of Molecular Biology, 230 (3). pp. 966-978. ISSN 0022-2836

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Abstract

Zinc induces transition of a d(GA·CT)22 sequence to a novel DNA conformation, called *H-DNA. In this paper, the structural characteristics of this altered DNA conformation are determined. Formation of *H-DNA is induced at zinc concentrations higher than 70 μM (Zn/P = 2) and it is favoured by negative supercoiling and low ionic strength. Two different structural conformations of the d(GA·CT)22 sequence are observed upon increasing the zinc concentration. At low zinc concentration (Zn/P<15), half of the purine strand falls back upon itself giving rise to the formation of an RRY intramolecular triplex (H*-triplex). At higher zinc concentration, the complete pyrimidine strand is single-stranded and an RR hairpin is formed (*H-hairpin). Protection towards dimethylsulphate modification suggests that zinc binds to the N-7 group of guanine residues in the *H-hairpin with a higher affinity than in B-DNA. The dissociation constant of the *H-zinc complex is estimated to be in the range of 10-3 M to 10-4 M.

Item Type:	Article
Uncontrolled Keywords:	homopurine·homopyrimidine sequences,non-b-dna structures,triplex dna,zinc-dna interactions,biophysics,structural biology,molecular biology ,/dk/atira/pure/subjectarea/asjc/1300/1304
Faculty \ School:	Faculty of Science > School of Biological Sciences
UEA Research Groups:	Faculty of Science > Research Groups > Biosciences Teaching and Education Research Faculty of Science > Research Groups > Molecular Microbiology Faculty of Science > Research Centres > Centre for Molecular and Structural Biochemistry
Related URLs:	https://www.scopus.com/pages/publication...
Depositing User:	LivePure Connector
Date Deposited:	18 May 2026 14:55
Last Modified:	18 May 2026 14:55
URI:	https://ueaeprints.uea.ac.uk/id/eprint/103074
DOI:	10.1006/jmbi.1993.1213

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