4ZC0

Structure of a dodecameric bacterial helicase

4ZC0 の概要

• エントリーDOI: 10.2210/pdb4zc0/pdb
• 関連するPDBエントリー: 3GXV 4A1F
• 分子名称: Replicative DNA helicase, HEXATANTALUM DODECABROMIDE (2 entities in total)
• 機能のキーワード: helicase atpase dna replication, dodecamer, hydrolase
• 由来する生物種: Helicobacter pylori
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 240406.96

構造登録者

Bazin, A.,Cherrier, M.V.,Gutsche, I.,Timmins, J.,Terradot, L. (登録日: 2015-04-15, 公開日: 2015-10-21, 最終更新日: 2024-05-08)

主引用文献

Bazin, A.,Cherrier, M.V.,Gutsche, I.,Timmins, J.,Terradot, L.
Structure and primase-mediated activation of a bacterial dodecameric replicative helicase.
Nucleic Acids Res., 43:8564-8576, 2015

PubMed Abstract: Replicative helicases are essential ATPases that unwind DNA to initiate chromosomal replication. While bacterial replicative DnaB helicases are hexameric, Helicobacter pylori DnaB (HpDnaB) was found to form double hexamers, similar to some archaeal and eukaryotic replicative helicases. Here we present a structural and functional analysis of HpDnaB protein during primosome formation. The crystal structure of the HpDnaB at 6.7 Å resolution reveals a dodecameric organization consisting of two hexamers assembled via their N-terminal rings in a stack-twisted mode. Using fluorescence anisotropy we show that HpDnaB dodecamer interacts with single-stranded DNA in the presence of ATP but has a low DNA unwinding activity. Multi-angle light scattering and small angle X-ray scattering demonstrate that interaction with the DnaG primase helicase-binding domain dissociates the helicase dodecamer into single ringed primosomes. Functional assays on the proteins and associated complexes indicate that these single ringed primosomes are the most active form of the helicase for ATP hydrolysis, DNA binding and unwinding. These findings shed light onto an activation mechanism of HpDnaB by the primase that might be relevant in other bacteria and possibly other organisms exploiting dodecameric helicases for DNA replication.

PubMed: 26264665
DOI: 10.1093/nar/gkv792

実験手法

X-RAY DIFFRACTION (6.7 Å)