ParAB Partition Dynamics in Firmicutes: Nucleoid Bound ParA Captures and Tethers ParB-Plasmid Complexes.

In Firmicutes, small homodimeric ParA-like (δ2) and ParB-like (ω2) proteins, in concert with cis-acting plasmid-borne parS and the host chromosome, secure stable plasmid inheritance in a growing bacterial population. This study shows that (ω:YFP)2 binding to parS facilitates plasmid clustering in the cytosol. (δ:GFP)2 requires ATP binding but not hydrolysis to localize onto the cell's nucleoid as a fluorescent cloud.

The Interplay between Different Stability Systems Contributes to Faithful Segregation: Streptococcus pyogenes pSM19035 as a Model.

The Streptococcus pyogenes pSM19035 low-copy-number θ-replicating plasmid encodes five segregation (seg) loci that contribute to plasmid maintenance. These loci map outside of the minimal replicon. The segA locus comprises β2 recombinase and two six sites, and segC includes segA and also the γ topoisomerase and two ssiA sites.

Molecular anatomy of the Streptococcus pyogenes pSM19035 partition and segrosome complexes.

Vancomycin or erythromycin resistance and the stability determinants, δω and ωεζ, of Enterococci and Streptococci plasmids are genetically linked. To unravel the mechanisms that promoted the stable persistence of resistance determinants, the early stages of Streptococcus pyogenes pSM19035 partitioning were biochemically dissected. First, the homodimeric centromere-binding protein, ω2, bound parS DNA to form a short-lived partition complex 1 (PC1).

Two discrete elements are required for the replication of a repABC plasmid: an antisense RNA and a stem-loop structure.

The repABC replicons contain an operon encoding the initiator protein (RepC) and partitioning proteins (RepA and RepB). The latter two proteins negatively regulate the transcription of the operon. In this article we have identified two novel regulatory elements, located within the conserved repB-repC intergenic sequence, which negatively modulate the expression of repC, in plasmid p42d of Rhizobium etli.