SMC head domain from Thermotoga maritima

Experimental Data Snapshot

  • Resolution: 3.10 Å
  • R-Value Free: 0.272 
  • R-Value Work: 0.250 
  • R-Value Observed: 0.250 

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This is version 1.5 of the entry. See complete history


Crystal Structure of the Smc Head Domain: An Abc ATPase with 900 Residues Antiparallel Coiled-Coil Inserted

Lowe, J.Cordell, S.C.van den Ent, F.

(2001) J Mol Biol 306: 25

  • DOI: https://doi.org/10.1006/jmbi.2000.4379
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    SMC (structural maintenance of chromosomes) proteins are large coiled-coil proteins involved in chromosome condensation, sister chromatid cohesion, and DNA double-strand break processing. They share a conserved five-domain architecture with three globular domains separated by two long coiled-coil segments. The coiled-coil segments are antiparallel, bringing the N and C-terminal globular domains together. We have expressed a fusion protein of the N and C-terminal globular domains of Thermotoga maritima SMC in Escherichia coli by replacing the approximately 900 residue coiled-coil and hinge segment with a short peptide linker. The SMC head domain (SMChd) binds and condenses DNA in an ATP-dependent manner. Using selenomethionine-substituted protein and multiple anomalous dispersion phasing, we have solved the crystal structure of the SMChd to 3.1 A resolution. In the monoclinic crystal form, six SMChd molecules form two turns of a helix. The fold of SMChd is closely related to the ATP-binding cassette (ABC) ATPase family of proteins and Rad50, a member of the SMC family involved in DNA double-strand break repair. In SMChd, the ABC ATPase fold is formed by the N and C-terminal domains with the 900 residue coiled-coil and hinge segment inserted in the middle of the fold. The crystal structure of an SMChd confirms that the coiled-coil segments in SMC proteins are anti-parallel and shows how the N and C-terminal domains come together to form an ABC ATPase. Comparison to the structure of the MukB N-terminal domain demonstrates the close relationship between MukB and SMC proteins, and indicates a helix to strand conversion when N and C-terminal parts come together.

  • Organizational Affiliation

    Laboratory of Molecular Biology, MRC, Hills Road, Cambridge, CB2 2QH, UK. jyl@mrc-lmb.cam.ac.uk

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D, E
A, B, C, D, E, F
322Thermotoga maritimaMutation(s): 0 
Find proteins for Q9X0R4 (Thermotoga maritima (strain ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826 / MSB8))
Explore Q9X0R4 
Go to UniProtKB:  Q9X0R4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9X0R4
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.10 Å
  • R-Value Free: 0.272 
  • R-Value Work: 0.250 
  • R-Value Observed: 0.250 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 134α = 90
b = 49.19β = 94.63
c = 233.88γ = 90
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-08-09
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-07-05
    Changes: Refinement description
  • Version 1.4: 2018-01-24
    Changes: Database references, Source and taxonomy
  • Version 1.5: 2024-05-08
    Changes: Data collection, Database references, Other