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-Structure paper
タイトル | Unwinding of a DNA replication fork by a hexameric viral helicase. |
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ジャーナル・号・ページ | Nat Commun, Vol. 12, Issue 1, Page 5535, Year 2021 |
掲載日 | 2021年9月20日 |
著者 | Abid Javed / Balazs Major / Jonathan A Stead / Cyril M Sanders / Elena V Orlova / |
PubMed 要旨 | Hexameric helicases are motor proteins that unwind double-stranded DNA (dsDNA) during DNA replication but how they are optimised for strand separation is unclear. Here we present the cryo-EM ...Hexameric helicases are motor proteins that unwind double-stranded DNA (dsDNA) during DNA replication but how they are optimised for strand separation is unclear. Here we present the cryo-EM structure of the full-length E1 helicase from papillomavirus, revealing all arms of a bound DNA replication fork and their interactions with the helicase. The replication fork junction is located at the entrance to the helicase collar ring, that sits above the AAA + motor assembly. dsDNA is escorted to and the 5´ single-stranded DNA (ssDNA) away from the unwinding point by the E1 dsDNA origin binding domains. The 3´ ssDNA interacts with six spirally-arranged β-hairpins and their cyclical top-to-bottom movement pulls the ssDNA through the helicase. Pulling of the RF against the collar ring separates the base-pairs, while modelling of the conformational cycle suggest an accompanying movement of the collar ring has an auxiliary role, helping to make efficient use of ATP in duplex unwinding. |
リンク | Nat Commun / PubMed:34545080 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 3.9 Å |
構造データ | EMDB-11852, PDB-7apd: |
由来 |
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キーワード | DNA BINDING PROTEIN / DNA / virus / helicase / replisome / DNA replication. |