Selective small-molecule inhibition of an RNA structural element

  • Nature. 2015 Oct 29;526(7575):672-7. doi: 10.1038/nature15542.
John A Howe  1 ,  Hao Wang  1 ,  Thierry O Fischmann  1 ,  Carl J Balibar  1 ,  Li Xiao  1 ,  Andrew M Galgoci  1 ,  Juliana C Malinverni  1 ,  Todd Mayhood  1 ,  Artjohn Villafania  1 ,  Ali Nahvi  2 ,  Nicholas Murgolo  1 ,  Christopher M Barbieri  1 ,  Paul A Mann  1 ,  Donna Carr  1 ,  Ellen Xia  1 ,  Paul Zuck  3 ,  Dan Riley  3 ,  Ronald E Painter  1 ,  Scott S Walker  1 ,  Brad Sherborne  1 ,  Reynalda de Jesus  1 ,  Weidong Pan  1 ,  Michael A Plotkin  1 ,  Jin Wu  1 ,  Diane Rindgen  1 ,  John Cummings  1 ,  Charles G Garlisi  1 ,  Rumin Zhang  1 ,  Payal R Sheth  1 ,  Charles J Gill  1 ,  Haifeng Tang  1 ,  Terry Roemer  1
Affiliations
  • 1. Merck Research Laboratories, Kenilworth, New Jersey 07033, USA.
  • 2. Merck Research Laboratories, West Point, Pennsylvania 19486, USA.
  • 3. Merck Research Laboratories, North Wales, Pennsylvania 19454, USA.
Abstract

Riboswitches are non-coding RNA structures located in messenger RNAs that bind endogenous ligands, such as a specific metabolite or ion, to regulate gene expression. As such, riboswitches serve as a novel, yet largely unexploited, class of emerging drug targets. Demonstrating this potential, however, has proven difficult and is restricted to structurally similar antimetabolites and semi-synthetic analogues of their cognate ligand, thus greatly restricting the chemical space and selectivity sought for such inhibitors. Here we report the discovery and characterization of ribocil, a highly selective chemical modulator of Bacterial riboflavin riboswitches, which was identified in a phenotypic screen and acts as a structurally distinct synthetic mimic of the natural ligand, flavin mononucleotide, to repress riboswitch-mediated ribB gene expression and inhibit Bacterial cell growth. Our findings indicate that non-coding RNA structural elements may be more broadly targeted by synthetic small molecules than previously expected.

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