8rwv | pdb_00008rwv
Human OCCM DNA licensing intermediate
Structural highlights
DiseaseMCM4_HUMAN Primary immunodeficiency with natural-killer cell deficiency and adrenal insufficiency. The disease is caused by mutations affecting the gene represented in this entry. FunctionMCM4_HUMAN Acts as component of the MCM2-7 complex (MCM complex) which is the putative replicative helicase essential for 'once per cell cycle' DNA replication initiation and elongation in eukaryotic cells. The active ATPase sites in the MCM2-7 ring are formed through the interaction surfaces of two neighboring subunits such that a critical structure of a conserved arginine finger motif is provided in trans relative to the ATP-binding site of the Walker A box of the adjacent subunit. The six ATPase active sites, however, are likely to contribute differentially to the complex helicase activity.[1] [2] Publication Abstract from PubMedHuman 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 ATPgammaS, 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. Reconstitution of human DNA licensing and the structural and functional analysis of key intermediates.,Wells JN, Edwardes LV, Leber V, Allyjaun S, Peach M, Tomkins J, Kefala-Stavridi A, Faull SV, Aramayo R, Pestana CM, Ranjha L, Speck C Nat Commun. 2025 Jan 8;16(1):478. doi: 10.1038/s41467-024-55772-z. PMID:39779677[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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