PT  - JOURNAL ARTICLE
AU  - Morgan Jones
AU  - Fabienne Beuron
AU  - Aaron Borg
AU  - Andrea Nans
AU  - Christopher Earl
AU  - David C. Briggs
AU  - Maureen Bowles
AU  - Edward P. Morris
AU  - Mark Linch
AU  - Neil Q. McDonald
TI  - Cryo-EM Structures of the XPF-ERCC1 Endonuclease Reveal an Auto-Inhibited Conformation and the Basis for Activation
AID  - 10.1101/796524
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 796524
4099  - http://biorxiv.org/content/early/2019/10/07/796524.short
4100  - http://biorxiv.org/content/early/2019/10/07/796524.full
AB  - The structure-specific endonuclease XPF-ERCC1 participates in multiple DNA damage repair pathways including nucleotide excision repair (NER) and inter-strand crosslink repair (ICLR). How XPF-ERCC1 is catalytically activated by DNA junction substrates is not currently understood. We report cryo-electron microscopy structures of both DNA-free and DNA-bound human XPF-ERCC1. DNA-free XPF-ERCC1 adopts an auto-inhibited conformation in which the XPF helical domain masks ERCC1 DNA-binding elements and restricts access to the XPF catalytic site. Binding of a model DNA junction separates the XPF helical and ERCC1 (HhH)2 domains, promoting activation. Using these structural data, we propose a model for a 5’-NER incision complex involving XPF-ERCC1-XPA and a DNA junction substrate. Structure-function data suggest xeroderma pigmentosum patient mutations often compromise the structural integrity of XPF-ERCC1. Fanconi anaemia patient mutations often display substantial in-vitro activity but are resistant to activation by ICLR recruitment factor SLX4. Our data provide insights into XPF-ERCC1 architecture and catalytic activation.