Periodontal diseases are the group of the most common diseases of the oral cavity. One of the more invasive forms of periodontal disease is aggressive periodontitis. In patients with aggressive periodontitis, a significantly increased number of Aggregatibacter actinomycetemcomitans (A. a.) has been found, which has a negative effect on the host tissue with its virulence factors. Using bioinformatics tools, they recently compiled a list of A. a. D7S proteins that are believed to interact with mRNA molecules in human cells. From the prepared list we selected 6 proteins (PNPase, DnaK, F0F1 ATP synthase, RPS1, TadG and ThrRS) and tested their influence on Saccharomyces cerevisiae yeasts, into which we transformed plasmid constructs with genes for the selected protein. Expression of the selected protein was induced when yeast carrying such plasmid construct was grown in medium containing galactose as the sole carbon source. We found that the growth of transformants with induced PNPase gene expression was completely inhibited. The same result was achieved by testing the effect of PNPase to which the 3x-FLAG tail was attached, which will be useful for further research. We have also successfully identified a key catalytic residue in PNPase, that when mutated, precluded the PNPase inhibitory effect. In addition, we also prepared a plasmid construct enabling the 3x-FLAG tagged PNPase expression from its native promoter in A. a. We anticipate that the results obtained in this study will provide a solid basis for further research on the effect of A. a. PNPase on the human cells.
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