Structural and Mechanistic Analysis of the Slx1-Slx4 Endonuclease

Vineet Gaur; Haley D M Wyatt; Weronika Komorowska; Roman H Szczepanowski; Daniele de Sanctis; Karolina M Gorecka; Stephen C West; Marcin Nowotny

doi:10.1016/j.celrep.2015.02.019

Structural and Mechanistic Analysis of the Slx1-Slx4 Endonuclease

Cell Rep. 2015 Mar 10;10(9):1467-1476. doi: 10.1016/j.celrep.2015.02.019. Epub 2015 Mar 5.

Authors

Vineet Gaur¹, Haley D M Wyatt², Weronika Komorowska¹, Roman H Szczepanowski³, Daniele de Sanctis⁴, Karolina M Gorecka¹, Stephen C West², Marcin Nowotny⁵

Affiliations

¹ Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Księcia Trojdena Street, 02-109 Warsaw, Poland.
² London Research Institute, Cancer Research UK, Clare Hall Laboratories, Blanche Lane, South Mimms, Herts EN6 3LD, UK.
³ Biophysics Core Facility, International Institute of Molecular and Cell Biology, 4 Księcia Trojdena Street, 02-109 Warsaw, Poland.
⁴ European Synchrotron Radiation Facility (ESRF), 71 Avenue des Martyrs, CS 40220, 38043 Grenoble Cédex 9, France.
⁵ Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Księcia Trojdena Street, 02-109 Warsaw, Poland. Electronic address: mnowotny@iimcb.gov.pl.

Abstract

The SLX1-SLX4 endonuclease required for homologous recombination and DNA repair in eukaryotic cells cleaves a variety of branched DNA structures. The nuclease subunit SLX1 is activated by association with a scaffolding protein SLX4. At the present time, little is known about the structure of SLX1-SLX4 or its mechanism of action. Here, we report the structural insights into SLX1-SLX4 by detailing the crystal structure of Candida glabrata (Cg) Slx1 alone and in combination with the C-terminal region of Slx4. The structure of Slx1 reveals a compact arrangement of the GIY-YIG nuclease and RING domains, which is reinforced by a long α helix. Slx1 forms a stable homodimer that blocks its active site. Slx1-Slx4 interaction is mutually exclusive with Slx1 homodimerization, suggesting a mechanism for Slx1 activation by Slx4.

Abstract

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