OriD structure controls RepD initiation during rolling-circle replication.

ABSTRACT: Bacterial antibiotic resistance is often carried by circular DNA plasmids that are copied separately from the genomic DNA and can be passed to other bacteria, spreading the resistance. The chloramphenicol-resistance plasmid pC221 from Staphylococcus aureus is duplicated by a process called asymmetric rolling circle replication. It is not fully understood how the replication process is regulated but its initiation requires a plasmid-encoded protein called RepD that nicks one strand of the parent plasmid at the double-stranded origin of replication (oriD). Using magnetic tweezers to control the DNA linking number we found RepD nicking occurred only when DNA was negatively supercoiled and that binding of a non-nicking mutant (RepDY188F) stabilized secondary structure formation at oriD. Quench

SUBMITTER: Toleikis A 

PROVIDER: S-EPMC5775427 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature