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RESEARCH PRODUCT
Can copper(II) mediate Hoogsteen base-pairing in a left-handed DNA duplex? A pulse EPR study
Maria Grazia SantangeloMaria Grazia SantangeloPhilipp M. AntoniBernhard SpinglerGunnar Jeschkesubject
10120 Department of ChemistryCircular dichroismGuanineStereochemistryHoogsteen base pairrame strutture del DNA basi nucleotidiche EPR a impulsi risonanza paramagneticachemistry.chemical_elementTriple-stranded DNA3107 Atomic and Molecular Physics and OpticsNucleobasechemistry.chemical_compoundPolydeoxyribonucleotidesDNA structures540 ChemistryDNA Z-FormPhysical and Theoretical ChemistryBase PairingTernary complexCircular Dichroismstructure elucidationElectron Spin Resonance Spectroscopypulse EPIR spectroscopynucleobasesCopperSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)Atomic and Molecular Physics and Opticschemistrycopper1606 Physical and Theoretical ChemistryCytosinedescription
Pulse EPR spectroscopy is sued to investigate possible structural features of the copper(II) ion coordinated to poly(dG-dC) poly(dG-dC) in a frozen aqueous solution, and the structural change of the polynucleotide induced by the presence of the metal ion. Two different copper species were identified and their geometry explained by a molecular model. According to this model, one species is exclusively coordinated to a single guanine with the N7 nitrogen atom forming a coordinative bond with the copper. In the other species, a guanine and a cytosine form a ternary complex together with the copper ion. A copper crosslink between the N7 of guanine and N3 of cytosine is proposed as the most probable coordination site. Moreover, no evidence was found for an interaction of either copper species with a phosphate group or equatorial water molecules. In addition, circular dichroism (CD) spectroscopy showed that the DNA of the Cu-II-poly(dG-dC)center dot poly(dG-dC) adducts resembles the left-handed Z-form. These results suggest that metal-mediated Hoogsteen base pairing, as previously proposed for a right-handed DNA duplex, can also occur in a double-stranded left-handed DNA.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2010-01-01 |