A dinuclear silver(I)-mediated base pair in DNA formed from 1, N-6-ethenoadenine and thymine

作者：Mandal Soham; Hebenbrock Marian; Mueller Jens

来源：Inorganica Chimica Acta, 2018, 472: 229-233.

DOI：10.1016/j.ica.2017.05.072

• Bioinorganic chemistry
• Nucleic acids
• Silver
• Metal-mediated base pair

The artificial nucleobase 1, N-6-ethenoadenine (epsilon A) is shown to form a dinuclear Ag(I)-mediated base pair with a complementary thymine (T) residue in double-helical DNA. The stabilizing effect brought about by the formation of such a metal-mediated base pair amounts to 5-6 degrees C. It does not depend on the orientation of the base pair within the duplex, i.e. the epsilon A-Ag(I)(2)-T base pair confers the same stability as the T-Ag(I)(2)-epsilon A base pair. Circular dichroism studies and temperature-dependent UV spectroscopy were applied to establish the formation of this Ag(I)-mediated base pair. Based on DFT calculations, a base pair configuration is proposed in which one Ag(I) ion is coordinated by epsilon A-N6 and T-O4, whereas the other Ag (I) ion forms coordinate bonds to eA-N7 and T-N3. The computations indicate a short intramolecular Ag center dot center dot center dot Ag contact of 2.87 angstrom, suggesting that argentophilic interactions may be involved.

• 出版日期2018-3-1