1. Crystal structures of the structure-selective nuclease Mus81-Eme1 bound to flap DNA substrates
- Author
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Kyeong Sik Jin, Jong-Bong Lee, Kyuwon Baek, Yunje Cho, Youngchang Kim, Aera Jo, Gwang Hyeon Gwon, and Yaoyao Fu
- Subjects
Models, Molecular ,5' Flanking Region ,DNA repair ,Flap structure-specific endonuclease 1 ,Crystallography, X-Ray ,General Biochemistry, Genetics and Molecular Biology ,Substrate Specificity ,Structure-Activity Relationship ,Endonuclease ,chemistry.chemical_compound ,Protein structure ,Humans ,DNA Breaks, Single-Stranded ,Protein Structure, Quaternary ,Molecular Biology ,Nuclease ,Endodeoxyribonucleases ,General Immunology and Microbiology ,biology ,General Neuroscience ,DNA ,Articles ,Endonucleases ,Molecular biology ,DNA-Binding Proteins ,chemistry ,biology.protein ,Biophysics ,Nucleic Acid Conformation ,Interstrand cross-link repair ,Homologous recombination ,Protein Binding - Abstract
The Mus81-Eme1 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 Mus81-Eme1 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 Mus81-Eme1 unexpectedly shares several common features with members of the 5′ flap nuclease family, the combined structural, biochemical, and biophysical analyses explain why Mus81-Eme1 preferentially cleaves 3′ flap DNA substrates with 5′ nicked ends.
- Published
- 2014
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