3F9V: Crystal Structure Of A Near Full-Length Archaeal Mcm: Functional Insights For An Aaa+ Hexameric Helicase

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.
PDB ID: 3F9VDownload
MMDB ID: 68834
PDB Deposition Date: 2008/11/14
Updated in MMDB: 2008/12
Experimental Method:
x-ray diffraction
Resolution: 4.35  Å
Source Organism:
Similar Structures:
Biological Unit for 3F9V: monomeric; determined by author and by software (PISA)
Molecular Components in 3F9V
Label Count Molecule
Protein (1 molecule)
Minichromosome Maintenance Protein MCM(Gene symbol: SSO_RS03895)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB