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Crystal structures of the structure‐selective nuclease M us81‐ E me1 bound to flap DNA substrates
Author(s) -
Gwon Gwang Hyeon,
Jo Aera,
Baek Kyuwon,
Jin Kyeong Sik,
Fu Yaoyao,
Lee JongBong,
Kim YoungChang,
Cho Yunje
Publication year - 2014
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/embj.201487820
Subject(s) - library science , biology , physics , computer science
Abstract The M us81‐ E me1 complex is a structure‐selective endonuclease with a critical role in the resolution of recombination intermediates during DNA repair after interstrand cross‐links, replication fork collapse, or double‐strand breaks. To explain the molecular basis of 3′ flap substrate recognition and cleavage mechanism by Mus81‐Eme1, we determined crystal structures of human M us81‐ E me1 bound to various flap DNA substrates. Mus81‐Eme1 undergoes gross substrate‐induced conformational changes that reveal two key features: (i) a hydrophobic wedge of Mus81 that separates pre‐ and post‐nick duplex DNA and (ii) a “5′ end binding pocket” that hosts the 5′ nicked end of post‐nick DNA . These features are crucial for comprehensive protein‐ DNA interaction, sharp bending of the 3′ flap DNA substrate, and incision strand placement at the active site. While M us81‐ E me1 unexpectedly shares several common features with members of the 5′ flap nuclease family, the combined structural, biochemical, and biophysical analyses explain why M us81‐ E me1 preferentially cleaves 3′ flap DNA substrates with 5′ nicked ends.