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- Title
The structure of SV40 large T hexameric helicase in complex with AT-rich origin DNA.
- Authors
Gai, Dahai; Damian Wang; Shu-Xing Li; Chen, Xiaojiang S.
- Abstract
DNA replication is a fundamental biological process. The initial step in eukaryotic DNA replication is the assembly of the pre-initiation complex, including the formation of two head-tohead hexameric helicases around the replication origin. How these hexameric helicases interact with their origin dsDNA remains unknown. Here, we report the co-crystal structure of the SV40 Large-T Antigen (LT) hexameric helicase bound to its origin dsDNA. The structure shows that the six subunits form a near-planar ring that interacts with the origin, so that each subunit makes unique contacts with the DNA. The origin dsDNA inside the narrower AAA+ domain channel shows partial melting due to the compression of the two phosphate backbones, forcing Watson-Crick base-pairs within the duplex to flip outward. This structure provides the first snapshot of a hexameric helicase binding to origin dsDNA, and suggests a possible mechanism of origin melting by LT during SV40 replication in eukaryotic cells.
- Subjects
EUKARYOTIC cell genetics; DNA replication; DNA helicase genetics; MOLECULAR structure of DNA helicases; APTAMERS
- Publication
eLife, 2016, p1
- ISSN
2050-084X
- Publication type
Article
- DOI
10.7554/eLife.18129