MIT Libraries logoDSpace@MIT

MIT
View Item 
  • DSpace@MIT Home
  • MIT Open Access Articles
  • MIT Open Access Articles
  • View Item
  • DSpace@MIT Home
  • MIT Open Access Articles
  • MIT Open Access Articles
  • View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.

A conserved Mcm4 motif is required for Mcm2-7 double-hexamer formation and origin DNA unwinding

Author(s)
Champasa, Kanokwan; Blank, Caitlin; Friedman, Larry J; Gelles, Jeff; Bell, Stephen P
Thumbnail
DownloadPublished version (2.676Mb)
Terms of use
Creative Commons Attribution 4.0 International license https://creativecommons.org/licenses/by/4.0/
Metadata
Show full item record
Abstract
Licensing of eukaryotic origins of replication requires DNA loading of two copies of the McM2-7 replicative helicase to form a head-to-head double-hexamer, ensuring activated helicases depart the origin bidirectionally. To understand the formation and importance of this double-hexamer, we identified mutations in a conserved and essential McM4 motif that permit loading of two McM2-7 complexes but are defective for double-hexamer formation. Single-molecule studies show mutant McM2-7 forms initial hexamer-hexamer interactions; however, the resulting complex is unstable. Kinetic analyses of wild-type and mutant McM2-7 reveal a limited time window for double-hexamer formation following second McM2-7 association, suggesting that this process is facilitated. Double-hexamer formation is required for extensive origin DNA unwinding but not initial DNA melting or recruitment of helicase-activation proteins (Cdc45, GINS, McM10). Our findings elucidate dynamic mechanisms of origin licensing, and identify the transition between initial DNA melting and extensive unwinding as the first initiation event requiring double-hexamer formation.
Date issued
2019-08
URI
https://hdl.handle.net/1721.1/126039
Department
Massachusetts Institute of Technology. Department of Biology
Journal
eLife
Publisher
eLife Sciences Publications, Ltd
Citation
Champasa, Kanokwan et al. "A conserved Mcm4 motif is required for Mcm2-7 double-hexamer formation and origin DNA unwinding." eLife 8: e45538 © 2019 Champasa et al.
Version: Final published version
ISSN
2050-084X

Collections
  • MIT Open Access Articles

Browse

All of DSpaceCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

My Account

Login

Statistics

OA StatisticsStatistics by CountryStatistics by Department
MIT Libraries
PrivacyPermissionsAccessibilityContact us
MIT
Content created by the MIT Libraries, CC BY-NC unless otherwise noted. Notify us about copyright concerns.