Structural characterization of filaments formed by human Xrcc4-Cernunnos/XLF complex involved in nonhomologous DNA end-joining

Virginie Ropars, Pascal Drevet, Pierre Legrand, Sonia Baconnais, Jeremy Amram, Guilhem Faure, José A. Márquez, Olivier Piétrement, Raphaël Guerois, Isabelle Callebaut, Eric Le Cam, Patrick Revy, Jean Pierre De Villartay, Jean Baptiste Charbonnier

Résultats de recherche: Contribution à un journalArticleRevue par des pairs

111 Citations (Scopus)

Résumé

Cernunnos/XLF is a core protein of the nonhomologous DNA end-joining (NHEJ) pathway that processes the majority of DNA double-strand breaks in mammals. Cernunnos stimulates the final ligation step catalyzed by the complex between DNA ligase IV and Xrcc4 (X4). Here we present the crystal structure of the X4 1-157- Cernunnos 1-224 complex at 5.5-Å resolution and identify the relative positions of the two factors and their binding sites. The X-ray structure reveals a filament arrangement for X4 1-157 and Cernunnos 1-224 homodimers mediated by repeated interactions through their N-terminal head domains. A filament arrangement of the X4-Cernunnos complex was confirmed by transmission electron microscopy analyses both with truncated and full-length proteins. We further modeled the interface and used structure-based site-directed mutagenesis and calorimetry to characterize the roles of various residues at the X4-Cernunnos interface. We identified four X4 residues (Glu 55, Asp 58, Met 61, and Phe 106) essential for the interaction with Cernunnos. These findings provide new insights into the molecular bases for stimulatory and bridging roles of Cernunnos in the final DNA ligation step.

langue originaleAnglais
Pages (de - à)12663-12668
Nombre de pages6
journalProceedings of the National Academy of Sciences of the United States of America
Volume108
Numéro de publication31
Les DOIs
étatPublié - 2 août 2011
Modification externeOui

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