Conscious uncoupling of riboswitch functions

Abstract

Riboswitches alter gene expression in response to ligand binding, coupling sensing and regulatory functions to help bacteria respond to their environment. The structural determinants of ligand binding in the prequeuosine (7-aminomethyl-7-deazaguanine, preQ₁) bacterial riboswitches have been studied, but the functional consequences of structural perturbations are less known. A new article combining biophysical and cell-based readouts of 15 mutants of the preQ₁-II riboswitch from Lactobacillus rhamnosus demonstrates that ligand binding does not ensure successful gene regulation, providing new insights into these shapeshifting sequences.

Figure 1.

Presentation of schematic function of riboswitches (left) and fragment of secondary structure of the Lrh preQ₁-II riboswitch WT sequence based on the crystal structure (5) (right). The various motifs of preQ1-II riboswitch investigated by Dutta and Wedekind (4) are highlighted in colored text.