Structure-Based Virtual Ligand Screening on the XRCC4/DNA Ligase IV Interface

Grégory Menchon (1) , Oriane Bombarde (1) , Mansi Trivedi (1) , Aurélie Négrel (2) , Cyril Inard (3) , Brigitte Guidetti (3) , Michel Baltas (3) , Alain Milon (1) , Mauro Modesti (2) , Georges Czaplicki (1) , Patrick Calsou (1)

1 IPBS - Institut de pharmacologie et de biologie structurale
2 CRCM - Centre de Recherche en Cancérologie de Marseille
3 SPCMIB - Synthèse et Physico-Chimie de Molécules d'Intérêt Biologique

DSBs cytotoxicity is largely exploited in anticancer therapy. Thus, NHEJ is an attractive target for strategies aimed at increasing the sensitivity of tumors to clastogenic anticancer treatments. However the high affinity of the XRCC4/Lig4 interaction and the extended protein-protein interface make drug screening on this target particularly challenging. Here, we conducted a pioneering study aimed at interfering with XRCC4/Lig4 assembly. By Molecular Dynamics simulation using the crystal structure of the complex, we first delineated the Lig4 clamp domain as a limited suitable target. Then, we performed in silico screening of ~95,000 filtered molecules on this Lig4 subdomain. Hits were evaluated by Differential Scanning Fluorimetry, Saturation Transfer Difference-NMR spectroscopy and interaction assays with purified recombinant proteins. In this way we identified the first molecule able to prevent Lig4 binding to XRCC4 in vitro. This compound has a unique tripartite interaction with the Lig4 clamp domain that suggests a starting chemotype for rational design of analogous molecules with improved affinity.

Domaines: Biologie structurale [q-bio.BM]

Grégory Menchon, Oriane Bombarde, Mansi Trivedi, Aurélie Négrel, Cyril Inard, et al.. Structure-Based Virtual Ligand Screening on the XRCC4/DNA Ligase IV Interface. Scientific Reports, 2015, 6, pp.22878. ⟨10.1038/srep22878⟩. ⟨hal-01456277⟩