Biological Assembly 1  

 3D View: Structure | Electron Density

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 23.37 kDa 
• Atom Count: 1515 
• Residue Count: 190 
• Unique protein chains: 1

2PNH

Escherichia coli PriB E39A variant

• DOI: 10.2210/pdb2PNH/pdb

• Classification: DNA BINDING PROTEIN
• Organism(s): Escherichia coli K-12
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): Yes 


• Deposited: 2007-04-24 Released: 2007-08-07 
• Deposition Author(s): Lopper, M.E., Keck, J.L.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.25 Å
• R-Value Free: 0.276 
• R-Value Work: 0.247 
• R-Value Observed: 0.248 

Literature

A hand-off mechanism for primosome assembly in replication restart.

Lopper, M., Boonsombat, R., Sandler, S.J., Keck, J.L.

(2007) Mol Cell 26: 781-793

• PubMed: 17588514 
• DOI: 10.1016/j.molcel.2007.05.012
• Primary Citation of Related Structures:  
  2PNH


• PubMed Abstract: 
  

Collapsed DNA replication forks must be reactivated through origin-independent reloading of the replication machinery (replisome) to ensure complete duplication of cellular genomes. In E. coli, the PriA-dependent pathway is the major replication restart mechanism and requires primosome proteins PriA, PriB, and DnaT for replisome reloading. However, the molecular mechanisms that regulate origin-independent replisome loading are not fully understood. Here, we demonstrate that assembly of primosome protein complexes represents a key regulatory mechanism, as inherently weak PriA-PriB and PriB-DnaT interactions are strongly stimulated by single-stranded DNA. Furthermore, the binding site on PriB for single-stranded DNA partially overlaps the binding sites for PriA and DnaT, suggesting a dynamic primosome assembly process in which single-stranded DNA is handed off from one primosome protein to another as a repaired replication fork is reactivated. This model helps explain how origin-independent initiation of DNA replication is restricted to repaired replication forks, preventing overreplication of the genome.

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Organizational Affiliation: 

Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, 550 Medical Sciences Center, 1300 University Avenue, Madison, WI 53706, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Primosomal replication protein n	A, B	107	Escherichia coli K-12	Mutation(s): 1  Gene Names: priB, b4201, JW4159
Find proteins for P07013 (Escherichia coli (strain K12)) Explore P07013  Go to UniProtKB:  P07013

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.25 Å
• R-Value Free: 0.276 
• R-Value Work: 0.247 
• R-Value Observed: 0.248 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 49.978	α = 90
b = 60.685	β = 90
c = 66.273	γ = 90

Software Package:

Software Name	Purpose
DENZO	data reduction
SCALEPACK	data scaling
AMoRE	phasing
REFMAC	refinement
PDB_EXTRACT	data extraction
HKL-2000	data collection
HKL-2000	data reduction
HKL-2000	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2007-04-24 
• Released Date: 2007-08-07 
Deposition Author(s): Lopper, M.E., Keck, J.L.

Revision History 

• Version 1.0: 2007-08-07
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Advisory, Derived calculations, Refinement description, Source and taxonomy, Version format compliance
• Version 1.2: 2017-10-18
  Changes: Refinement description