DNA unwinding mechanism of a eukaryotic replicative CMG helicase
نویسندگان
چکیده
منابع مشابه
Action of CMG with strand-specific DNA blocks supports an internal unwinding mode for the eukaryotic replicative helicase
Replicative helicases are ring-shaped hexamers that encircle DNA for duplex unwinding. The currently accepted view of hexameric helicase function is by steric exclusion, where the helicase encircles one DNA strand and excludes the other, acting as a wedge with an external DNA unwinding point during translocation. Accordingly, strand-specific blocks only affect these helicases when placed on the...
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The Mcm2-7 complex serves as the eukaryotic replicative helicase, the molecular motor that both unwinds duplex DNA and powers fork progression during DNA replication. Consistent with its central role in this process, much prior work has illustrated that Mcm2-7 loading and activation are landmark events in the regulation of DNA replication. Unlike any other hexameric helicase, Mcm2-7 is composed...
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A prerequisite for DNA replication is the unwinding of duplex DNA catalyzed by a replicative hexameric helicase. Despite a growing body of research, key elements of helicase mechanism remain under substantial debate. In particular, the number of DNA strands encircled by the helicase ring during unwinding and the ring orientation at the replication fork completely contrast in contemporary mechan...
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In eukaryotes, two Mcm2–7 rings are loaded onto DNA at origins of replication during G1 phase1,2. The double hexamer is inactive as a heli case but is activated upon entry into S phase by the Dbf4dependent Cdc7 kinase, cyclindependent kinase and several transient factors that activate origins; subsequently, Cdc45 and GINS assemble onto each Mcm2–7 complex, thereby forming two active CMG heli...
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The mechanism of DNA translocation by papillomavirus E1 and polyomavirus LTag hexameric helicases involves consecutive remodelling of subunit-subunit interactions around the hexameric ring. Our biochemical analysis of E1 helicase demonstrates that a 26-residue C-terminal segment is critical for maintaining the hexameric assembly. As this segment was not resolved in previous crystallographic ana...
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ژورنال
عنوان ژورنال: Nature Communications
سال: 2020
ISSN: 2041-1723
DOI: 10.1038/s41467-020-14577-6