Functional analysis of a palindromic sequence required for normal replication of several staphylococcal plasmids.

摘要: Abstract Most small multicopy antibiotic-resistance plasmids of Staphylococcus aureus contain a major axis hyphenated dyad symmetry (palA) that is required for normal replication and stability, although located outside the minimal replicon. Rearrangements affecting palA cause plasmid instability, marked reduction in copy number, accumulation large quantities strand-specific circular single-stranded DNA. In view recent observation pT181 initiates by nick 3'-extension mechanism (S. Khan, personal communication), it suggested these replicate an asymmetric rolling-circle which displaced plus strand remains single stranded until exposed, forming hairpin serves as lagging origin.