4ESV

A New Twist on the Translocation Mechanism of Helicases from the Structure of DnaB with its Substrates

4ESV の概要

• エントリーDOI: 10.2210/pdb4esv/pdb
• 分子名称: 5'-D(P*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*T)-3', 5'-D(P*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*TP*T)-3', Replicative helicase, ... (8 entities in total)
• 機能のキーワード: reca fold, helicase, hydrolase-dna complex, hydrolase/dna
• 由来する生物種: Geobacillus stearothermophilus; 詳細
• タンパク質・核酸の鎖数: 14
• 化学式量合計: 623320.43

構造登録者

Itsathitphaisarn, O.,Wing, R.A.,Eliason, W.K.,Wang, J.,Steitz, T.A. (登録日: 2012-04-23, 公開日: 2012-10-24, 最終更新日: 2024-02-28)

主引用文献

Itsathitphaisarn, O.,Wing, R.A.,Eliason, W.K.,Wang, J.,Steitz, T.A.
The Hexameric Helicase DnaB Adopts a Nonplanar Conformation during Translocation.
Cell(Cambridge,Mass.), 151:267-277, 2012

PubMed Abstract: DNA polymerases can only synthesize nascent DNA from single-stranded DNA (ssDNA) templates. In bacteria, the unwinding of parental duplex DNA is carried out by the replicative DNA helicase (DnaB) that couples NTP hydrolysis to 5' to 3' translocation. The crystal structure of the DnaB hexamer in complex with GDP-AlF(4) and ssDNA reported here reveals that DnaB adopts a closed spiral staircase quaternary structure around an A-form ssDNA with each C-terminal domain coordinating two nucleotides of ssDNA. The structure not only provides structural insights into the translocation mechanism of superfamily IV helicases but also suggests that members of this superfamily employ a translocation mechanism that is distinct from other helicase superfamilies. We propose a hand-over-hand mechanism in which sequential hydrolysis of NTP causes a sequential 5' to 3' movement of the subunits along the helical axis of the staircase, resulting in the unwinding of two nucleotides per subunit.

PubMed: 23022319
DOI: 10.1016/j.cell.2012.09.014

実験手法

X-RAY DIFFRACTION (3.2 Å)