Crystal Structure Of A Near Full-Length Archaeal MCM: Functional Insights For An AAA+ Hexameric Helicase

Experimental Data Snapshot

  • Resolution: 4.35 Å
  • R-Value Free: 0.481 
  • R-Value Work: 0.412 
  • R-Value Observed: 0.415 

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Crystal structure of a near-full-length archaeal MCM: Functional insights for an AAA+ hexameric helicase.

Brewster, A.S.Wang, G.Yu, X.Greenleaf, W.B.Carazo, J.M.Tjajadia, M.Klein, M.G.Chen, X.S.

(2008) Proc Natl Acad Sci U S A 105: 20191-20196

  • DOI: https://doi.org/10.1073/pnas.0808037105
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The minichromosome maintenance protein (MCM) complex is an essential replicative helicase for DNA replication in Archaea and Eukaryotes. Whereas the eukaryotic complex consists of 6 homologous proteins (MCM2-7), the archaeon Sulfolobus solfataricus has only 1 MCM protein (ssoMCM), 6 subunits of which form a homohexamer. Here, we report a 4.35-A crystal structure of the near-full-length ssoMCM. The structure shows an elongated fold, with 5 subdomains that are organized into 2 large N- and C-terminal domains. A near-full-length ssoMCM hexamer generated based on the 6-fold symmetry of the N-terminal Methanothermobacter thermautotrophicus (mtMCM) hexamer shows intersubunit distances suitable for bonding contacts, including the interface around the ATP pocket. Four unusual beta-hairpins of each subunit are located inside the central channel or around the side channels in the hexamer. Additionally, the hexamer fits well into the double-hexamer EM map of mtMCM. Our mutational analysis of residues at the intersubunit interfaces and around the side channels demonstrates their critical roles for hexamerization and helicase function. These structural and biochemical results provide a basis for future study of the helicase mechanisms of the archaeal and eukaryotic MCM complexes in DNA replication.

  • Organizational Affiliation

    Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Minichromosome maintenance protein MCM595Saccharolobus solfataricusMutation(s): 0 
Gene Names: MCMSSO0774
EC: 3
Find proteins for Q9UXG1 (Saccharolobus solfataricus (strain ATCC 35092 / DSM 1617 / JCM 11322 / P2))
Explore Q9UXG1 
Go to UniProtKB:  Q9UXG1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9UXG1
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 4.35 Å
  • R-Value Free: 0.481 
  • R-Value Work: 0.412 
  • R-Value Observed: 0.415 
  • Space Group: I 41 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 202.526α = 90
b = 202.526β = 90
c = 128.243γ = 90
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
HKL-2000data collection
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: 2008-12-30
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2023-12-27
    Changes: Data collection, Database references