A novel mode of nuclease action is revealed by the bacterial Mre11/Rad50 complex |
| |
Authors: | Chew Theng Lim Pey Jiun Lai David?R.?F. Leach Hisaji Maki Asako Furukohri |
| |
Affiliation: | 1.Division of Systems Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan;2.Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Kings Buildings, Edinburgh EH9 3JR, UK |
| |
Abstract: | The Mre11/Rad50 complex is a central player in various genome maintenance pathways. Here, we report a novel mode of nuclease action found for the Escherichia coli Mre11/Rad50 complex, SbcC2/D2 complex (SbcCD). SbcCD cuts off the top of a cruciform DNA by making incisions on both strands and continues cleaving the dsDNA stem at ∼10-bp intervals. Using linear-shaped DNA substrates, we observed that SbcCD cleaved dsDNA using this activity when the substrate was 110 bp long, but that on shorter substrates the cutting pattern was changed to that predicted for the activity of a 3′-5′ exonuclease. Our results suggest that SbcCD processes hairpin and linear dsDNA ends with this novel DNA end-dependent binary endonuclease activity in response to substrate length rather than using previously reported activities. We propose a model for this mode of nuclease action, which provides new insight into SbcCD activity at a dsDNA end. |
| |
Keywords: | |
|
|