Publication Details (including relevant citation information):
CRYSTAL GROWTH & DESIGN, Volume: 10, Issue: 2, Pages: 676-684,Published: FEB 2010
Abstract: A DNA-like duplex of nucleosides is probable to exist even without the 5'-phosphate groups needed to assemble the chain backbone. However, double-stranded helical structures of nucleosides are unknown. Here, we report a duplex of nucleoside analogs that is spontaneously assembled due to stacking of the neutral and protonated molecules of lamivudine, a nucleoside reverse transcriptase inhibitor (NTRI) widely used in anti-HIV drug combinatory medication. The left-handed lamivudine duplex has features similar to those of i-motif DNA, as the face-to-face base stacking and the helix rise per base pair. Furthermore, the protonation pattern on alternate bases expected for it DNA-like duplex stabilized by pairing of neutral and protonated cytosine fragments was observed for the first time in the lamivudine double-stranded helix. This structure demonstrates that hydrogen bonds can substitute for covalent phosphodiester linkage in the stabilization of the duplex backbone. This interesting example of spontaneous molecular self-organization indicates that the 5'-phosphate group could not be a requirement for duplex assembly.
Address (URL): http://pubs.acs.org/doi/abs/10.1021/cg901103r