2gxa
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Crystal structure of papillomavirus E1 hexameric helicase with ssDNA and MgADP
OverviewOverview
The E1 protein of papillomavirus is a hexameric ring helicase belonging to the AAA + family. The mechanism that couples the ATP cycle to DNA translocation has been unclear. Here we present the crystal structure of the E1 hexamer with single-stranded DNA discretely bound within the hexamer channel and nucleotides at the subunit interfaces. This structure demonstrates that only one strand of DNA passes through the hexamer channel and that the DNA-binding hairpins of each subunit form a spiral 'staircase' that sequentially tracks the oligonucleotide backbone. Consecutively grouped ATP, ADP and apo configurations correlate with the height of the hairpin, suggesting a straightforward DNA translocation mechanism. Each subunit sequentially progresses through ATP, ADP and apo states while the associated DNA-binding hairpin travels from the top staircase position to the bottom, escorting one nucleotide of single-stranded DNA through the channel. These events permute sequentially around the ring from one subunit to the next.
About this StructureAbout this Structure
2GXA is a Single protein structure of sequence from Bovine papillomavirus type 1 with , and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Mechanism of DNA translocation in a replicative hexameric helicase., Enemark EJ, Joshua-Tor L, Nature. 2006 Jul 20;442(7100):270-5. PMID:16855583
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