Effect of the PotN Protein on Activities of the GlnR and PotA Proteins in the Cells of Lentilactobacillus hilgardii

Bacterial PII-like proteins are global regulators of nitrogen and energy metabolism, which respond to nutrients availability by binding cognate partner proteins, thus modulating their activity. The PotN protein from Lentilactobacillus hilgardii, a member of the new family of PII-like proteins, is capable of competitive binding of ATP and ADP, thus regulating metabolism in response to the cell energy status. Thus, under ADP excess, PotN binds this nucleotide and interacts mostly with the PotA subunit of the polyamine АВС transporter, suppressing its ATPase activity. PotN also dissociates from the transcription factor GlnR, restoring its ability to bind DNA and modulate expression of the genes of the GlnR regulon. On the contrary, in the ATP state PotN dissociates from PotA and binds to the GlnR factor.