PDBsum entry 4zc0

Hydrolase

PDB id: 4zc0

Contents

Protein chains

445 a.a.

148 a.a.

Ligands

TBR

PDB id:

4zc0

Name:

Hydrolase

Title:

Structure of a dodecameric bacterial helicase

Structure:

Replicative DNA helicase. Chain: a, b, c, d. Engineered: yes

Source:

Helicobacter pylori. Organism_taxid: 210. Gene: dnab, hp_1362. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

6.70Å R-factor: 0.260 R-free: 0.299

Authors:

A.Bazin,M.V.Cherrier,I.Gutsche,J.Timmins,L.Terradot

Key ref:

A.Bazin et al. (2015). Structure and primase-mediated activation of a bacterial dodecameric replicative helicase. Nucleic Acids Res, 43, 8564-8576. PubMed id: 26264665 DOI: 10.1093/nar/gkv792

Date:

15-Apr-15 Release date: 21-Oct-15

Protein chains

O25916  (DNAB_HELPY) -  Replicative DNA helicase from Helicobacter pylori (strain ATCC 700392 / 26695)

Seq: 488 a.a.

Struc: 445 a.a.

Protein chains

O25916  (DNAB_HELPY) -  Replicative DNA helicase from Helicobacter pylori (strain ATCC 700392 / 26695)

Seq: 488 a.a.

Struc: 148 a.a.

Enzyme reactions

• Enzyme class: Chains A, B, C, D: E.C.3.6.4.12 - Dna helicase.
• Reaction: ATP + H2O = ADP + phosphate + H⁺

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1093/nar/gkv792

Nucleic Acids Res 43:8564-8576 (2015)

PubMed id: 26264665

Structure and primase-mediated activation of a bacterial dodecameric replicative helicase.

A.Bazin, M.V.Cherrier, I.Gutsche, J.Timmins, L.Terradot.

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.