Concerted dynamics of metallo-base pairs in an A/B-form helical transition.

ABSTRACT: Metal-mediated base pairs expand the repertoire of nucleic acid structures and dynamics. Here we report solution structures and dynamics of duplex DNA containing two all-natural C-Hg^II-T metallo base pairs separated by six canonical base pairs. NMR experiments reveal a 3:1 ratio of well-resolved structures in dynamic equilibrium. The major species contains two (N3)T-Hg^II-(N3)C base pairs in a predominantly B-form helix. The minor species contains (N3)T-Hg^II-(N4)C base pairs and greater A-form characteristics. Ten-fold different ¹J coupling constants (¹⁵N,¹⁹⁹Hg) are observed for (N3)C-Hg^II (114 Hz) versus (N4)C-Hg^II (1052 Hz) connectivities, reflecting differences in cytosine ionization and metal-bonding

SUBMITTER: Schmidt OP 

PROVIDER: S-EPMC6811676 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature