Ys. Rhee et al., NITROGEN-15-LABELED OLIGODEOXYNUCLEOTIDES .6. USE OF N-15 NMR TO PROBE BINDING OF NETROPSIN AND DISTAMYCIN TO (D[CGCGAATTCGCG])2, Journal of the American Chemical Society, 115(19), 1993, pp. 8742-8746
The binding of netropsin and distamycin to the duplex {d[CGCGAATTCGCG]
}2, in which adenine residues A5 or A6 were [3-N-15] labeled, was moni
tored by N-15 NMR to probe the sensitivity of these N-15 labels to dru
g binding. The N-15 chemical shifts were obtained from a H-1-N-15 hete
ronuclear 2D experiment. The N-15 atoms in the asymmetric complexes we
re assigned with use of, in addition, a H-1-H-1 2D NOESY experiment. T
he results for both complexes show that water is excluded from the cen
ter of the binding site, and that there is hydrogen bonding to the N3
at the common propylamidinium termini of the drugs. Further, in the di
stamycin complex, there is a second drug.H bond at the formamide termi
nus of the drug. These results demonstrate that these N-15 labels are
useful monitors of drug binding.