Subcellular Localization and Characterization of the ParAB System fromCorynebacterium glutamicum

Abstract

Faithful segregation of chromosomes and plasmids is a vital prerequisite to produce viable and genetically identical progeny. Bacteria use a specialized segregation system composed of the partitioning proteins ParA and ParB to segregate certain plasmids. Strikingly, homologues of ParA and ParB are found to be encoded in many chromosomes. Although mutations in the chromosomal Par system have effects on segregation efficiency, the exact mechanism by which the chromosomes are segregated into the daughter cells is not fully understood. We describe the polar localization of the ParB origin nucleoprotein complex in the actinomycete Corynebacterium glutamicum. ParB and the origin of replication were found to be stably localized to the cell poles. After replication, the origins move toward the opposite pole. Purified ParB was able to bind to the parS consensus sequence in vitro. C. glutamicum possesses two ParA-like partitioning ATPase proteins. Both proteins interact with ParB but show a slightly different subcellular localization and phenotype. While ParA might be part of a conventional partitioning system, PldP seems to play a role in division site selection.

Antibacterial Activity of Alkyl Gallates against Xanthomonas citri subsp. citri

“…The bacterial centromere is constituted by ParB bound to DNA at specific cis-acting elements (parS) located around the origin of replication of the chromosomes (e.g., Bacillus subtilis [33]). As proposed previously, ParB functions by interacting with other cellular factors to facilitate chromosome partitioning toward the polar regions, enabling cell division to proceed (34)(35)(36). Thus, ParB-GFP colocalizes with the origins, and the centromere structure formed can be seen by fluorescence microscopy as two foci, each close to a cell pole (37,38).…”

“…Chromosome segregation and cell division are two essential and interlinked processes in bacteria (34,52,53). Direct links between components of the two processes (e.g., FtsZ and ParB via an FtsZ inhibitor such as MipZ in C. crescentus) have been demonstrated (34,36). Curiously, we found recently that X. citri subsp.…”

Functional Characterization of pGKT2, a 182-Kilobase Plasmid Containing the xplAB Genes, Which Are Involved in the Degradation of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine by Gordonia sp. Strain KTR9

“…The second predicted plasmid replication protein is a ParA homolog whose gene, KTR9_4794, is located approximately 1.5 kb upstream of KTR9_4798. The encoded protein shares 34% amino acid sequence identity with the functionally characterized ParA of Corynebacterium glutamicum ATCC 13032 (20) and 68% identity with the predicted ParA homolog from Rhodococcus opacus B4. Predicted ParA homologs from actinomycete plasmids, including homologs from each of the three KTR9 plasmids, were aligned using ClustalX.…”

Topoisomerase I (TopA) Is Recruited to ParB Complexes and Is Required for Proper Chromosome Organization during Streptomyces coelicolor Sporulation

“…The positioning of ParB complexes is facilitated by their interaction with polymers of ParA protein, which exhibit dynamic properties associated with their ATPase activity (12,13). The deletion of the genes encoding ParA and/or ParB leads to disturbed chromosome segregation and the formation of anucleate cells, with the extent dependent on the species and growth conditions (from 1% in Bacillus subtilis [14,15] to 43% in C. glutamicum grown on minimal medium [16]). …”