Common and distinctive features of GNRA tetraloops based on a GUAA tetraloop structure at 1.4 Å resolution

Structural overview and lattice contacts. (A) Schematic of the RNA sequence in the crystal structure showing the tetraloop (green), bulged-G motif (yellow), the flexible region (blue), and the stem region (red). Gray arrows indicate the two adenosines and WC base pairs involved in lattice contacts that mimic A-minor like interactions (Fig. 3). The sites of mutation are underlined. (B) A ribbon drawing of the GUAA mutant structure.