A DNA-binding protein implicated in transcriptional repression and chromosome organization and compaction. Binds DNA, modifying gene expression, especially non-core genes. Does not regulate the same set of genes as its chromosomal counterpart (tested in S.typhimurium strain SL1344 / SV5015, chromosomal H-NS protein is AC A0A0H3NBY9). Thus it has a not-completely overlapping set of gene targets compared to its chromosomal homolog; many of these target genes are either plasmid-encoded or acquired by horizontally transferred genes (HTG). This protein can function in the absence of H-NS-modulating protein Hha (either chromosomal or plasmid-encoded), although many HTG genes are regulated by an H-NS/Hha complex (PubMed:19521501). Binds nucleation sites in AT-rich DNA and bridges them, forming higher-order nucleoprotein complexes and condensing the chromosome (By similarity). A subset of genes are repressed by H-NS in association with Hha and/or Cnu (ydgT) (By similarity). Homodimer that oligomerizes on DNA into higher-order complexes that form bridges between disparate regions of DNA compacting it. Interacts with Hha, YdgT and StpA. This protein is encoded on incompatibility group H (IncHI) plasmid R27, a temperature-sensitive conjugative plasmid. Belongs to the histone-like protein H-NS family.