Silver-Mediated Homochiral and Heterochiral ?-dC/?-dC Base Pairs: Synthesis of ?-dC through Glycosylation and Impact of Consecutive, Isolated, and Multiple Metal Ion Pairs on DNA Stability.

ABSTRACT: Isolated and consecutive heterochiral ?-dC- base pairs have been incorporated into 12-mer oligonucleotide duplexes at various positions, thereby replacing Watson-Crick pairs. To this end, a new synthesis of the ?-d anomer of dC has been developed, and oligonucleotides containing ?-dC residues have been synthesized. Silver-mediated base pairs were formed upon the addition of silver ions. Furthermore, we have established that heterochiral ?-dC-dC base pairs can approach the stability of a Watson-Crick pair, whereas homochiral dC-dC pairs are significantly less stable. A positional change of the silver-mediated base pairs affects the duplex stability and reveals the nearest-neighbor influence. When the number of silver ions was equivalent to the number of duplex base pairs (12), non-melting silver-rich complexes were formed. Structural changes have been supported by circular dichroism (CD) spectra, which showed that the B-DNA structure was maintained whilst the silver ion concentration was low. At high silver ion concentration, silver-rich complexes displaying different CD spectra were formed.

SUBMITTER: Chai Y 

PROVIDER: S-EPMC6972701 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature