DjR1

DjR1 is a protein‑coding gene identified in the bacterium Staphylococcus aureus. The gene encodes a small, basic protein of approximately 160 amino acids that belongs to the COG1967 family of transcriptional regulators. It is also annotated as SA1132 and was first discovered in 1999 during comparative genomic studies of methicillin‑resistant strains. Sequence analysis reveals a helix‑turn‑helix DNA‑binding motif and a positively charged C‑terminal tail, indicating a role in binding promoter regions of genes associated with cell wall synthesis and stress response.

Functional studies of S. aureus mutants lacking djr1 show that the protein aids in adaptation to high‑salt and oxidative conditions. Transcriptomic profiling indicates that loss of DjR1 reduces expression of the vraS/vraR two‑component system and increases sensitivity to β‑lactam antibiotics. Comparative genomics demonstrates that djr1-like sequences are conserved across other Gram‑positive pathogens, including Bacillus subtilis and Enterococcus faecalis, suggesting a shared regulatory function.

Current research efforts aim to elucidate the structure of the DjR1‑DNA complex through X‑ray crystallography and to identify small‑molecule inhibitors that could disrupt its activity and restore antibiotic susceptibility. While no clinical applications have yet been reported, DjR1 is considered a potential target in the development of new antimicrobial agents.