Crystal structure of the single-stranded dna-binding protein from mycobacterium tuberculosis

Experimental Data Snapshot

  • Resolution: 2.50 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.228 

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Structure of Mycobacterium tuberculosis single-stranded DNA-binding protein. Variability in quaternary structure and its implications

Saikrishnan, K.Jeyakanthan, J.Venkatesh, J.Acharya, N.Sekar, K.Varshney, U.Vijayan, M.

(2003) J Mol Biol 331: 385-393

  • DOI: https://doi.org/10.1016/s0022-2836(03)00729-0
  • Primary Citation of Related Structures:  
    1UE1, 1UE5, 1UE6, 1UE7

  • PubMed Abstract: 

    Single-stranded DNA-binding protein (SSB) is an essential protein necessary for the functioning of the DNA replication, repair and recombination machineries. Here we report the structure of the DNA-binding domain of Mycobacterium tuberculosis SSB (MtuSSB) in four different crystals distributed in two forms. The structure of one of the forms was solved by a combination of isomorphous replacement and anomalous scattering. This structure was used to determine the structure of the other form by molecular replacement. The polypeptide chain in the structure exhibits the oligonucleotide binding fold. The globular core of the molecule in different subunits in the two forms and those in Escherichia coli SSB (EcoSSB) and human mitochondrial SSB (HMtSSB) have similar structure, although the three loops exhibit considerable structural variation. However, the tetrameric MtuSSB has an as yet unobserved quaternary association. This quaternary structure with a unique dimeric interface lends the oligomeric protein greater stability, which may be of significance to the functioning of the protein under conditions of stress. Also, as a result of the variation in the quaternary structure the path adopted by the DNA to wrap around MtuSSB is expected to be different from that of EcoSSB.

  • Organizational Affiliation

    Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Single-strand binding protein
A, B
164Mycobacterium tuberculosisMutation(s): 0 
Find proteins for P9WGD5 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Explore P9WGD5 
Go to UniProtKB:  P9WGD5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP9WGD5
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on ZN

Download Ideal Coordinates CCD File 
C [auth B]ZINC ION
Experimental Data & Validation

Experimental Data

  • Resolution: 2.50 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.228 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 78.72α = 90
b = 78.72β = 90
c = 77.16γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2004-02-10
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-12-27
    Changes: Data collection, Database references, Derived calculations