Structural maintenance of chromosomes protein of Bacillus subtilis affects supercoiling in vivo.

摘要: Structural maintenance of chromosomes (SMC) proteins are found in nearly all organisms. Members this protein family involved chromosome condensation and sister chromatid cohesion. Bacillus subtilis SMC (BsSMC) plays a role organization partitioning. To better understand the function BsSMC, we studied effects an smc null mutation on DNA supercoiling vivo. We that mutant was hypersensitive to gyrase inhibitors coumermycin A1 norfloxacin. Furthermore, depleting cells topoisomerase I substantially suppressed partitioning defect mutant. Plasmid isolated from more negatively supercoiled than wild-type cells. In vivo cross-linking experiments indicated BsSMC bound plasmid. Our results indicate affects vivo, most likely by constraining positive supercoils, activity which contributes compaction organization.