5meb
Crystal structure of yeast Cdt1 C-terminal domainCrystal structure of yeast Cdt1 C-terminal domain
Structural highlights
FunctionCDT1_YEAST DNA replication licensing factor, required for pre-replication complex assembly. Faithful duplication of the genetic material requires 'once per cell cycle' DNA replication initiation and elongation. Central to this control is the tightly regulated formation of prereplicative complexes (preRCs) at future origins of DNA replication. Required for the recruitment of the MCM2-7 helicase complex to the replication origins.[1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedORC, Cdc6 and Cdt1 act together to load hexameric MCM, the motor of the eukaryotic replicative helicase, into double hexamers at replication origins. Here we show that Cdt1 interacts with MCM subunits Mcm2, 4 and 6, which both destabilizes the Mcm2-5 interface and inhibits MCM ATPase activity. Using X-ray crystallography, we show that Cdt1 contains two winged-helix domains in the C-terminal half of the protein and a catalytically inactive dioxygenase-related N-terminal domain, which is important for MCM loading, but not for subsequent replication. We used these structures together with single-particle electron microscopy to generate three-dimensional models of MCM complexes. These show that Cdt1 stabilizes MCM in a left-handed spiral open at the Mcm2-5 gate. We propose that Cdt1 acts as a brace, holding MCM open for DNA entry and bound to ATP until ORC-Cdc6 triggers ATP hydrolysis by MCM, promoting both Cdt1 ejection and MCM ring closure. Cdt1 stabilizes an open MCM ring for helicase loading.,Frigola J, He J, Kinkelin K, Pye VE, Renault L, Douglas ME, Remus D, Cherepanov P, Costa A, Diffley JFX Nat Commun. 2017 Jun 23;8:15720. doi: 10.1038/ncomms15720. PMID:28643783[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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