Fig. 3: Structures of SAM-VI riboswitch bound to non-cognate SAH and a ligand mimic.
From: SAM-VI riboswitch structure and signature for ligand discrimination
a Chemical structure of SAH. b SAM-VI binding pocket interactions with SAH (for discussion see main text). c Detailed view of the SAH-adenine U8 base pair. The composite omit electron-density map of SAH contoured at the 1.0 σ level is shown in light gray. d Chemical structure of the ligand mimic (M1). e SAM-VI binding pocket interactions with M1 (for discussion see main text). f Detailed view of the M1-adenine U8 base pair. The composite omit electron-density map of M1 contoured at the 1.0 σ level is shown in light gray. g, h Exemplary ITC titration experiments of SAM-VI riboswitch binding with SAH and the ligand mimic M1, respectively; for arithmetic means of Kd values and thermodynamic parameters see Table 1 and Supplementary Table 2.
