Structural characterization of the native oligomerization mode of MvaT proteins in <i>Pseudomonas</i>

strains typically harbor plasmids encoding MvaT proteins, while enterobacteria carry plasmids encoding H-NS. Our results suggest that differences in the oligomerization domain of H-NS family proteins may be critical for the cross-talk between plasmids and the host chromosome.IMPORTANCEHorizontal gene transfer is a major driver of microbial evolution. H-NS family proteins are key factors in optimizing the transcription of newly acquired genes in host cells. Despite high sequence diversity among bacteria, these proteins share the ability to form oligomers along DNA, a critical property for their function. H-NS family proteins encoded both on large transmissible plasmids and on the chromosomes of host cells play an important role in the successful integration of new genetic sequences into the regulatory networks of microbes. Bacterial hosts typically harbor plasmids encoding the same type of H-NS family proteins as found on their chromosomes. Here, we characterized the structural basis for oligomerization of MvaT proteins, members of the H-NS family proteins in pseudomonads. Our findings reveal differences between the oligomerization mode of MvaT proteins and H-NS in enterobacteria, suggesting that these differences might impact the transmission routes of plasmids within microbial communities.