1SE8

Structure of single-stranded DNA-binding protein (SSB) from D. radiodurans


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.217 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal structure of the Deinococcus radiodurans single-stranded DNA-binding protein suggests a mechanism for coping with DNA damage.

Bernstein, D.A.Eggington, J.M.Killoran, M.P.Misic, A.M.Cox, M.M.Keck, J.L.

(2004) Proc.Natl.Acad.Sci.USA 101: 8575-8580

  • DOI: 10.1073/pnas.0401331101

  • PubMed Abstract: 
  • Single-stranded DNA (ssDNA)-binding (SSB) proteins are uniformly required to bind and protect single-stranded intermediates in DNA metabolic pathways. All bacterial and eukaryotic SSB proteins studied to date oligomerize to assemble four copies of a ...

    Single-stranded DNA (ssDNA)-binding (SSB) proteins are uniformly required to bind and protect single-stranded intermediates in DNA metabolic pathways. All bacterial and eukaryotic SSB proteins studied to date oligomerize to assemble four copies of a conserved domain, called an oligonucleotide/oligosaccharide-binding (OB) fold, that cooperate in nonspecific ssDNA binding. The vast majority of bacterial SSB family members function as homotetramers, with each monomer contributing a single OB fold. However, SSB proteins from the Deinococcus-Thermus genera are exceptions to this rule, because they contain two OB folds per monomer. To investigate the structural consequences of this unusual arrangement, we have determined a 1.8-A-resolution x-ray structure of Deinococcus radiodurans SSB. The structure shows that D. radiodurans SSB comprises two OB domains linked by a beta-hairpin motif. The protein assembles a four-OB-fold arrangement by means of symmetric dimerization. In contrast to homotetrameric SSB proteins, asymmetry exists between the two OB folds of D. radiodurans SSB because of sequence differences between the domains. These differences appear to reflect specialized roles that have evolved for each domain. Extensive crystallographic contacts link D. radiodurans SSB dimers in an arrangement that has important implications for higher-order structures of the protein bound to ssDNA. This assembly utilizes the N-terminal OB domain and the beta-hairpin structure that is unique to Deinococcus and Thermus species SSB proteins. We hypothesize that differences between D. radiodurans SSB and homotetrameric bacterial SSB proteins may confer a selective advantage to D. radiodurans cells that aids viability in environments that challenge genomic stability.


    Organizational Affiliation

    Department of Biomolecular Chemistry, 550 Medical Science Center, 1300 University Avenue, University of Wisconsin Medical School, Madison, WI 53706-1532, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Single-strand binding protein
A
301Deinococcus radiodurans (strain ATCC 13939 / DSM 20539 / JCM 16871 / LMG 4051 / NBRC 15346 / NCIMB 9279 / R1 / VKM B-1422)Mutation(s): 0 
Gene Names: ssb
Find proteins for Q9RY51 (Deinococcus radiodurans (strain ATCC 13939 / DSM 20539 / JCM 16871 / LMG 4051 / NBRC 15346 / NCIMB 9279 / R1 / VKM B-1422))
Go to UniProtKB:  Q9RY51
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.217 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 91.347α = 90.00
b = 63.476β = 106.27
c = 54.907γ = 90.00
Software Package:
Software NamePurpose
SOLVEphasing
MOSFLMdata reduction
CCP4data scaling
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-06-15
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Advisory, Refinement description, Version format compliance