PMID: 24095061

Authors:

Grigg JC, Ke A

Title:

Structural Determinants for Geometry and Information Decoding of tRNA by T Box Leader RNA.

Journal:

Structure. 2013 Oct 1. pii: S0969-2126(13)00346-8. doi:, 10.1016/j.str.2013.09.001.

Abstract:

T box riboswitches are cis-acting RNA elements that bind to tRNA and sense its aminoacylation state to influence gene expression. Here, we present the 3.2 A resolution X-ray crystal structures of the T box Stem I-tRNA complex and tRNA, in isolation. T box Stem I forms an arched conformation with extensive intermolecular contacts to two key points of tRNA, the anticodon and D/T-loops. Free and complexed tRNA exist in significantly different conformations, with the contacts stabilizing flexible D/T-loops and a rearrangement of the D-loop. Using a designed T box RNA/tRNA system, we demonstrate that the T box riboswitch monitors the length and orientation of two essential contacts. Length or orientation mismatches engineered into the T box riboswitch and tRNA disrupt the complex, whereas simultaneous insertion of full helical turns realigns the interfaces and restores interaction between artificially elongated T box riboswitch and tRNA molecules.