Fig. 1

Characterization of the chromosomal ori region of H. neptunium. a Location of the chromosomal replication origin. The plot shows the relative abundance of chromosomal loci in growing H. neptunium wild-type cells, as determined by sequencing-based marker frequency analysis. The green line indicates the average of the data points. The values obtained for the hemE and dnaA loci are indicated by red dots. b Schematic representation of the parAB locus. The positions of the two parS sites identified in the H. neptunium genome sequence are indicated. c Purity of the ParB preparation used in the binding assay. Purified ParB-His₆ (10 µg) was subjected to SDS-PAGE and stained with Coomassie blue. A molecular weight standard is shown for comparison. d Interaction of ParB with its parS target sequence. Cy3-labeled double-stranded DNA oligonucleotides (10 nM) carrying the wild-type (left) or a mutated (right) parS sequence, respectively, were incubated with increasing concentrations of ParB-His₆ (0, 0.05, 0.1, 0.3, and 0.6 µM). Nucleoprotein complexes were separated from the free oligonucleotides by PAGE and visualized by fluorescence imaging. Red letters indicate substitutions in the parS sequence