Summary information and primary citation

PDB-id
5ean; DSSR-derived features in text and JSON formats
Class
hydrolase-DNA
Method
X-ray (2.36 Å)
Summary
Crystal structure of dna2 in complex with a 5' overhang DNA
Reference
Zhou C, Pourmal S, Pavletich NP (2015): "Dna2 nuclease-helicase structure, mechanism and regulation by Rpa." Elife, 4. doi: 10.7554/eLife.09832.
Abstract
The Dna2 nuclease-helicase maintains genomic integrity by processing DNA double-strand breaks, Okazaki fragments and stalled replication forks. Dna2 requires ssDNA ends, and is dependent on the ssDNA-binding protein Rpa, which controls cleavage polarity. Here we present the 2.3 Å structure of intact mouse Dna2 bound to a 15-nucleotide ssDNA. The nuclease active site is embedded in a long, narrow tunnel through which the DNA has to thread. The helicase domain is required for DNA binding but not threading. We also present the structure of a flexibly-tethered Dna2-Rpa interaction that recruits Dna2 to Rpa-coated DNA. We establish that a second Dna2-Rpa interaction is mutually exclusive with Rpa-DNA interactions and mediates the displacement of Rpa from ssDNA. This interaction occurs at the nuclease tunnel entrance and the 5' end of the Rpa-DNA complex. Hence, it only displaces Rpa from the 5' but not 3' end, explaining how Rpa regulates cleavage polarity.

Cartoon-block schematics in six views (download the tarball)

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