8RWV

Human OCCM DNA licensing intermediate

Summary for 8RWV

• Entry DOI: 10.2210/pdb8rwv/pdb
• EMDB information: 19566
• Descriptor: DNA replication licensing factor MCM2, Origin recognition complex subunit 5, Cell division control protein 6 homolog, ... (14 entities in total)
• Functional Keywords: dna replication, mcm2-7, dna licensing, human, origin, orc, pre-rc, cdc6, cdt1, replication
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 14
• Total formula weight: 967374.10

Authors

Wells, J.N.,Leber, V.,Edwards, L.V.,Allyjaun, S.,Peach, M.,Tomkins, J.,Kefala-Stavridi, A.,Faull, S.V.,Aramayo, R.,Pestana, C.M.,Ranjha, L.,Speck, C. (deposition date: 2024-02-05, release date: 2025-02-05)

Primary citation

Wells, J.N.,Edwardes, L.V.,Leber, V.,Allyjaun, S.,Peach, M.,Tomkins, J.,Kefala-Stavridi, A.,Faull, S.V.,Aramayo, R.,Pestana, C.M.,Ranjha, L.,Speck, C.
Reconstitution of human DNA licensing and the structural and functional analysis of key intermediates.
Nat Commun, 16:478-478, 2025

PubMed Abstract: Human DNA licensing initiates replication fork assembly and DNA replication. This reaction promotes the loading of the hMCM2-7 complex on DNA, which represents the core of the replicative helicase that unwinds DNA during S-phase. Here, we report the reconstitution of human DNA licensing using purified proteins. We showed that the in vitro reaction is specific and results in the assembly of high-salt resistant hMCM2-7 double-hexamers. With ATPγS, an hORC1-5-hCDC6-hCDT1-hMCM2-7 (hOCCM) assembles independent of hORC6, but hORC6 enhances double-hexamer formation. We determined the hOCCM structure, which showed that hORC-hCDC6 recruits hMCM2-7 via five hMCM winged-helix domains. The structure highlights how hORC1 activates the hCDC6 ATPase and uncovered an unexpected role for hCDC6 ATPase in complex disassembly. We identified that hCDC6 binding to hORC1-5 stabilises hORC2-DNA interactions and supports hMCM3-dependent recruitment of hMCM2-7. Finally, the structure allowed us to locate cancer-associated mutations at the hCDC6-hMCM3 interface, which showed specific helicase loading defects.

PubMed: 39779677
DOI: 10.1038/s41467-024-55772-z

Experimental method

ELECTRON MICROSCOPY (6.68 Å)