8EAK

SsoMCM hexamer bound to Mg/ADP-BeFx and 46-mer DNA strand. Class 2

This is a non-PDB format compatible entry.

Summary for 8EAK

• Entry DOI: 10.2210/pdb8eak/pdb
• Related: 8EAF 8EAG 8EAH 8EAI 8EAJ 8EAL 8EAM
• EMDB information: 27974 27975 27976 27977 27978 27979 27980 27981
• Descriptor: Minichromosome maintenance protein MCM, 46-mer DNA, ZINC ION, ... (6 entities in total)
• Functional Keywords: helicase, atpase, replication, transferase-dna complex, transferase/dna
• Biological source: Saccharolobus solfataricus P2; More
• Total number of polymer chains: 7
• Total formula weight: 428286.19

Authors

Meagher, M.,Myasnikov, A.,Enemark, E.J. (deposition date: 2022-08-29, release date: 2022-12-14, Last modification date: 2024-06-19)

Primary citation

Meagher, M.,Myasnikov, A.,Enemark, E.J.
Two Distinct Modes of DNA Binding by an MCM Helicase Enable DNA Translocation.
Int J Mol Sci, 23:-, 2022

PubMed Abstract: A six-subunit ATPase ring forms the central hub of the replication forks in all domains of life. This ring performs a helicase function to separate the two complementary DNA strands to be replicated and drives the replication machinery along the DNA. Disruption of this helicase/ATPase ring is associated with genetic instability and diseases such as cancer. The helicase/ATPase rings of eukaryotes and archaea consist of six minichromosome maintenance (MCM) proteins. Prior structural studies have shown that MCM rings bind one encircled strand of DNA in a spiral staircase, suggesting that the ring pulls this strand of DNA through its central pore in a hand-over-hand mechanism where the subunit at the bottom of the staircase dissociates from DNA and re-binds DNA one step above the staircase. With high-resolution cryo-EM, we show that the MCM ring of the archaeal organism binds an encircled DNA strand in two different modes with different numbers of subunits engaged to DNA, illustrating a plausible mechanism for the alternating steps of DNA dissociation and re-association that occur during DNA translocation.

PubMed: 36499022
DOI: 10.3390/ijms232314678

Experimental method

ELECTRON MICROSCOPY (2.67 Å)