Gaur Vineet, Wyatt Haley D M, Komorowska Weronika, Szczepanowski Roman H, de Sanctis Daniele, Gorecka Karolina M, West Stephen C, Nowotny Marcin
Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, 4 Księcia Trojdena Street, 02-109 Warsaw, Poland.
London Research Institute, Cancer Research UK, Clare Hall Laboratories, Blanche Lane, South Mimms, Herts EN6 3LD, UK.
Cell Rep. 2015 Mar 10;10(9):1467-1476. doi: 10.1016/j.celrep.2015.02.019. Epub 2015 Mar 5.
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.
真核细胞中同源重组和DNA修复所需的SLX1 - SLX4核酸酶可切割多种分支DNA结构。核酸酶亚基SLX1通过与支架蛋白SLX4结合而被激活。目前，人们对SLX1 - SLX4的结构及其作用机制知之甚少。在此，我们通过详细阐述光滑念珠菌（Cg）单独的Slx1以及与Slx4的C末端区域结合的晶体结构，报告了对SLX1 - SLX4的结构见解。Slx1的结构揭示了GIY - YIG核酸酶和RING结构域的紧密排列，这由一个长α螺旋加强。Slx1形成稳定的同源二聚体，封闭其活性位点。Slx1 - Slx4相互作用与Slx1同源二聚化相互排斥，提示了一种由Slx4激活Slx1的机制。
