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A novel mode of nuclease action is revealed by the bacterial Mre11/Rad50 complex.

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.

SUBMITTER: Lim CT

PROVIDER: S-EPMC4787754 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

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A novel mode of nuclease action is revealed by the bacterial Mre11/Rad50 complex.

Lim Chew Theng CT Lai Pey Jiun PJ Leach David R F DR Maki Hisaji H Furukohri Asako A

Nucleic acids research 20150828 20

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 subs ...[more]

PMID: 26319016

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