Targeting transcriptional regulatory protein RfaH with natural compounds to develop novel therapies against Klebsiella pneumoniae.

The growing threat of antibiotic-resistant K. pneumoniae infections demands novel treatment strategies. This study focuses on the transcriptional regulatory protein RfaH, a protein crucial for the bacteria's virulence by promoting gene expression for its capsule, cell wall, and pilus. As K. pneumoniae becomes resistant to existing antibiotics, targeting RfaH with specific inhibitors offers a promising alternative. The diverse benefits of natural compounds, including efficacy against microbial diseases, modulation of inflammatory processes, and potential in cancer therapy, have led to their increasing use in medicine. Through natural compound screening, we aimed to identify potential RfaH inhibitors and understand their interactions with the active site pocket of RfaH. Disrupting interactions of specific residues in RfaH by ligand binding could offer a means to interfere with its function selectively. We found that Naringenin and Quercetin have a strong binding affinity for RfaH β'CH binding pocket and form stable complexes, as evident from the MD simulation studies. The binding affinity of Naringenin and Quercetin was further validated experimentally by fluorescence measurements. This knowledge can be used to design potent and selective RfaH inhibitors for a new therapeutic approach to combat K. pneumoniae infections and address the urgent need for effective treatments.