Novel Anti-Repression Mechanism of H-NS Proteins by Phage’s “Early Proteins”

Bacteria and their associated bacteriophages are in a continuous battle, co-evolving defence, offence mechanisms. Bacterial xenogeneic silencers, H-NS family proteins, play important roles bacterial phage defence evolution by silencing incoming genes acquired through horizontal gene transfer. It is anticipated that the repression of these directly dependent on DNA binding modes proteins. proteins bind along DNA, forming lateral protein filaments, which protomers adopt “half-open” conformational state. Under specific environmental conditions without dissociation from an “open” state can bridge two duplexes. This switching direct effect electrostatic interactions between oppositely charged N-terminal domains The Pseudomonas lytic LUZ24 encodes gp4 binds MvaT aeruginosa. Binding was suggested to inhibit MvaT. However, mechanism modulates action remains elusive. this study, we show interferes with formation stability bridged MvaT-DNA complex. Structural investigations NMR paramagnetic spectroscopies revealed acts as “electrostatic zipper” stabilizes conformation. Based observations propose Mip promotes half-open - bridging incompetent MvaT, resulting relief MvaT-mediated silencing, has negative impact P. aeruginosa homeostasis fitness. Our survey uncovers novel anti-repression “early proteins” opens new avenue emulating antimicrobial small chemical compounds fight multidrug-resistance.