B. subtilis SsbB/ssDNA

Experimental Data Snapshot

  • Resolution: 2.80 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.230 
  • R-Value Observed: 0.232 

wwPDB Validation   3D Report Full Report

This is version 1.2 of the entry. See complete history


Genetic recombination in Bacillus subtilis: a division of labor between two single-strand DNA-binding proteins.

Yadav, T.Carrasco, B.Myers, A.R.George, N.P.Keck, J.L.Alonso, J.C.

(2012) Nucleic Acids Res 40: 5546-5559

  • DOI: https://doi.org/10.1093/nar/gks173
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    We have investigated the structural, biochemical and cellular roles of the two single-stranded (ss) DNA-binding proteins from Bacillus subtilis, SsbA and SsbB. During transformation, SsbB localizes at the DNA entry pole where it binds and protects internalized ssDNA. The 2.8-Å resolution structure of SsbB bound to ssDNA reveals a similar overall protein architecture and ssDNA-binding surface to that of Escherichia coli SSB. SsbA, which binds ssDNA with higher affinity than SsbB, co-assembles onto SsbB-coated ssDNA and the two proteins inhibit ssDNA binding by the recombinase RecA. During chromosomal transformation, the RecA mediators RecO and DprA provide RecA access to ssDNA. Interestingly, RecO interaction with ssDNA-bound SsbA helps to dislodge both SsbA and SsbB from the DNA more efficiently than if the DNA is coated only with SsbA. Once RecA is nucleated onto the ssDNA, RecA filament elongation displaces SsbA and SsbB and enables RecA-mediated DNA strand exchange. During plasmid transformation, RecO localizes to the entry pole and catalyzes annealing of SsbA- or SsbA/SsbB-coated complementary ssDNAs to form duplex DNA with ssDNA tails. Our results provide a mechanistic framework for rationalizing the coordinated events modulated by SsbA, SsbB and RecO that are crucial for RecA-dependent chromosomal transformation and RecA-independent plasmid transformation.

  • Organizational Affiliation

    Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, 28049 Madrid, Spain.


Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Single-stranded DNA-binding protein ssbB
A, B
116Bacillus subtilisMutation(s): 0 
Gene Names: ssbBywpHBSU36310
Find proteins for C0SPB6 (Bacillus subtilis (strain 168))
Explore C0SPB6 
Go to UniProtKB:  C0SPB6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupC0SPB6
Sequence Annotations
  • Reference Sequence
Find similar nucleic acids by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains LengthOrganismImage
C, D, E, F, G
35synthetic construct
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.80 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.230 
  • R-Value Observed: 0.232 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 101.753α = 90
b = 101.753β = 90
c = 118.571γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHENIXmodel building
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-03-14
    Type: Initial release
  • Version 1.1: 2012-07-25
    Changes: Database references
  • Version 1.2: 2024-02-28
    Changes: Data collection, Database references