Fig. 4
From: Identification of functional tetramolecular RNA G-quadruplexes derived from transfer RNAs
Substitution of guanines in 5ʹTOG motif with 7-deazaguanine prevents RG4 formation. a 7-deazaguanine derivative replaces the azide group at position 7 with a methine group (highlighted). Interaction with the hydrogen of the methine group is essential for Hoogsteen basepairing in a G-quartet. b Guanines at position 2 and 4 in the 5ʹTOG motif of 5ʹtiRNAAla were substituted with 7-deazaguanine (c, d) 5ʹtiRNAAla(WT) or 5ʹtiRNAAla(7daG) were equilibrated overnight in indicated salt solution and analyzed on denaturing c or native d gel and post-stained with SYBR gold (left panels) to detect total RNA or NMM (right panels) to detect RG4 structures. Regardless of ionic condition, 5ʹtiRNAAla(7daG) failed to form RG4 structure highlighting the importance of Hoogsteen base pairing for RG4 formation
