1D imino proton spectrum, 2D TOCSY, and 2D NOESY spectra of Apt1-S in H2O. 1D imino proton spectrum and 2D NOESY spectra of Apt1-S (mixing time = 150 msec). NOE connectivities are indicated by lines in the lower NOESY spectrum. Assignments were determined by NOE connectivities for imino proton resonances of G1–G2–G3–U34–U5–G6–G7 and U27–G26–G25 and are shown on top of the 1D imino proton spectrum. NOE connectivities are indicated by lines. Cross peaks between the NH2 (H41 and H42) –NH (H1) of C14–G23 and C16–G21 base pairs are shown. Cross peaks of intraresidue NOEs between H41–H42, NH2–H5, and H5–H6 of C14 and C16 are shown. (Red) The TOCSY spectrum superimposed on the NOESY spectrum. Assignments of NOE signals between NH2–NH were confirmed by these NOE connectivities. Assignments of NOE signals between H5–H6 were confirmed by sequential connectivities, as shown in Figure 5.
