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-Structure paper
タイトル | Mechanisms of opening and closing of the bacterial replicative helicase. |
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ジャーナル・号・ページ | Elife, Vol. 7, Year 2018 |
掲載日 | 2018年12月24日 |
著者 | Jillian Chase / Andrew Catalano / Alex J Noble / Edward T Eng / Paul Db Olinares / Kelly Molloy / Danaya Pakotiprapha / Martin Samuels / Brian Chait / Amedee des Georges / David Jeruzalmi / |
PubMed 要旨 | Assembly of bacterial ring-shaped hexameric replicative helicases on single-stranded (ss) DNA requires specialized loading factors. However, mechanisms implemented by these factors during opening and ...Assembly of bacterial ring-shaped hexameric replicative helicases on single-stranded (ss) DNA requires specialized loading factors. However, mechanisms implemented by these factors during opening and closing of the helicase, which enable and restrict access to an internal chamber, are not known. Here, we investigate these mechanisms in the DnaB helicase•bacteriophage λ helicase loader (λP) complex. We show that five copies of λP bind at DnaB subunit interfaces and reconfigure the helicase into an open spiral conformation that is intermediate to previously observed closed ring and closed spiral forms; reconfiguration also produces openings large enough to admit ssDNA into the inner chamber. The helicase is also observed in a restrained inactive configuration that poises it to close on activating signal, and transition to the translocation state. Our findings provide insights into helicase opening, delivery to the origin and ssDNA entry, and closing in preparation for translocation. |
リンク | Elife / PubMed:30582519 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 4.1 Å |
構造データ | |
化合物 | ChemComp-ADP: |
由来 |
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キーワード | REPLICATION / Helicase Loader / Helicase / DNA replication / ATPase / DNA Replication Initiation / Bacteriophage Lambda |