(A) Expanded plot showing NOEs from the imino protons to amino protons for the duplex containing the Tg6·G19 base pair. The cross-peaks are assigned as follows: a, G11N2H2→G11 N1H; b, C14N4H2→G11 N1H; c, C22 H5→G3 N1H; d, G3N2H2→G3 N1H; e, A23 H2→G3 N1H; f, C4N4H2→G3 N1H; g, C22N4H2→G3 N1H; h, C18 H5→G7 N1H; i, G7N2H2→G7 N1H; j, A17 H2→G7 N1H; k, C18N4H2→G7 N1H; l, C4 H5→G21 N1H; m, G21N2H2→G21 N1H; n, C4N4H2→G21 N1H; o, A23 H2→T2 N3H; p, A17N6H2→T8 N3H; q, A16N6H2→T8 N3H; r, A15N6H2→T10 N3H; s, A16 H2→T10 N3H; t, A15 H2→T10 N3H; u, A17 H2→T8 N3H; v, C18N4H2→T8 N3H; w, A16N6H2→T9 N3H; x, A16 H2→T9 N3H; y, A15 H2→T9 N3H; z, A16N6H1→T9 N3H; A, A17 H2→T9 N3H. (B) Expanded plot showing the sequential NOE connectivity for the imino protons of the duplex containing the Tg6·G19 base pair. The data were collected at 800 MHz at a 250 ms mixing time and a temperature of 7 °C.