A helicase-tethered ORC flip enables bidirectional helicase loading.

ABSTRACT: Replication origins are licensed by loading two Mcm2-7 helicases around DNA in a head-to-head conformation poised to initiate bidirectional replication. This process requires origin-recognition complex (ORC), Cdc6, and Cdt1. Although different Cdc6 and Cdt1 molecules load each helicase, whether two ORC proteins are required is unclear. Using colocalization single-molecule spectroscopy combined with single-molecule Förster resonance energy transfer (FRET), we investigated interactions between ORC and Mcm2-7 during helicase loading. In the large majority of events, we observed a single ORC molecule recruiting both Mcm2-7/Cdt1 complexes via similar interactions that end upon Cdt1 release. Between first- and second-helicase recruitment, a rapid change in interactions between ORC and the first

SUBMITTER: Gupta S 

PROVIDER: S-EPMC8828053 | biostudies-literature | 2021 Dec

REPOSITORIES: biostudies-literature