5-Mercuricytosine: An Organometallic Janus Nucleobase

: Ukale D, Shinde VS, Lönnberg T

Publisher: WILEY-V C H VERLAG GMBH

: 2016

: Chemistry - A European Journal

: CHEMISTRY-A EUROPEAN JOURNAL

: CHEM-EUR J

: 22

: 23

: 7917

: 7923

: 7

: 0947-6539

: 1521-3765

DOI: https://doi.org/10.1002/chem.201600851

The base-pairing properties of 5-mercuricytosine have been explored at the monomer level by NMR titrations and at the oligonucleotide level by melting temperature measurements. The NMR studies revealed a relatively high affinity for guanine, hypoxanthine, and uridine, that is, bases that are deprotonated upon coordination of Hg-II. Within an oligonucleotide duplex, 5-mercuricytosine formed Hg-II-mediated base pairs with thymine and guanine. In the former case, the duplex formed was as stable as the respective duplex comprising solely Watson-Crick base pairs. Based on detailed thermodynamic analysis of the melting curves, the stabilization by the Hg-II-mediated base pairs may be attributed to a comparatively low entropic penalty of hybridization.