4POG: MCM-ssDNA co-crystal structure

The ring-shaped MCM helicase is essential to all phases of DNA replication. The complex loads at replication origins as an inactive double-hexamer encircling duplex DNA. Helicase activation converts this species to two active single hexamers that encircle single-stranded DNA (ssDNA). The molecular details of MCM DNA interactions during these events are unknown. We determined the crystal structure of the Pyrococcus furiosus MCM N-terminal domain hexamer bound to ssDNA and define a conserved MCM-ssDNA binding motif (MSSB). Intriguingly, ssDNA binds the MCM ring interior perpendicular to the central channel with defined polarity. In eukaryotes, the MSSB is conserved in several Mcm2-7 subunits, and MSSB mutant combinations in S. cerevisiae Mcm2-7 are not viable. Mutant Mcm2-7 complexes assemble and are recruited to replication origins, but are defective in helicase loading and activation. Our findings identify an important MCM-ssDNA interaction and suggest it functions during helicase activation to select the strand for translocation. DOI: http://dx.doi.org/10.7554/eLife.01993.001.
PDB ID: 4POGDownload
MMDB ID: 119085
PDB Deposition Date: 2014/2/25
Updated in MMDB: 2017/12
Experimental Method:
x-ray diffraction
Resolution: 3.203  Å
Source Organism:
Pyrococcus furiosus DSM 3638
Similar Structures:
Biological Unit for 4POG: octameric; determined by author and by software (PISA)
Molecular Components in 4POG
Label Count Molecule
Proteins (6 molecules)
Cell Division Control Protein 21
Molecule annotation
Nucleotide(1 molecule)
30-mer Oligo(dt)
Molecule annotation
Chemicals (6 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB