Figure 1
From: An RNA tertiary switch by modifying how helices are tethered
Secondary structure of tRNA (a,c) and TYMV TLS (b,d) in cloverleaf (a,b) and L-shape (c,d) conformations. A, acceptor; AC, anticodon; V, variable. Red lines denote the linchpin in TLS and the corresponding junction in tRNA; dotted lines represent the interactions lost following removal of the 5’-UUAG sequence. (a) The cloverleaf diagram shows that the junction between the D- and A-stems found in tRNA is absent in TLS, but the linchpin forms an interaction in its place. (b) The L-shape fold of the TLS is stabilized by the linchpin interaction. Destabilizing this interaction allows it to extend, as shown by the arrows, whereas the closed junction of tRNA prevents this extension.