Fribourg, S.; Bure, C.; Florio, A. V.

Among the many proteins involved in cancer progression an increasing number of RNA Binding Proteins (RBPs) are central to the function of a cell and tightly associated to genetic diseases as well as cancer appearance and progression. In a recent study, small molecule inhibitors have been identified as targeting NONO, a RBP known to be involved in mRNA splicing, DNA repair and membraneless organelles stability. Here we report the molecular basis of NONO-targeting by the -chloroacetamide (R)-SKBG-1. We explore the specific binding and enantiomer specificity of NONO towards (R)-SKBG-1 using mass spectrometry and structure determination. We have determined the crystal structure of (R)-SKBG-1-bound to NONO homodimer. This study sheds light on the conformational plasticity of (R)-SKBG-1 when covalently bound to NONO. Altogether these results give an experimental rationale for ligand modification and optimization in a future use as a drug against cancer.