title: Molecular basis for the distinct divalent cation requirement in the uridylylation of the signal transduction proteins GlnJ and GlnB from Rhodospirillum rubrum.
abstract: BACKGROUND
  PII proteins have a fundamental role in the control of nitrogen metabolism in bacteria, through interactions with different PII targets, controlled by metabolite binding and post-translational modification, uridylylation in most organisms. In the photosynthetic bacterium Rhodospirillum rubrum, the PII proteins GlnB and GlnJ were shown, in spite of their high degree of similarity, to have different requirements for post-translational uridylylation, with respect to the divalent cations, Mg(2+) and Mn(2+).
  
  
  RESULTS
  Given the importance of uridylylation in the functional interactions of PII proteins, we have hypothesized that the difference in the divalent cation requirement for the uridylylation is related to efficient binding of Mg/Mn-ATP to the PII proteins. We concluded that the amino acids at positions 42 and 85 in GlnJ and GlnB (in the vicinity of the ATP binding site) influence the divalent cation requirement for uridylylation catalyzed by GlnD.
  
  
  CONCLUSIONS
  Efficient binding of Mg/Mn-ATP to the PII proteins is required for uridylylation by GlnD. Our results show that by simply exchanging two amino acid residues, we could modulate the divalent cation requirement in the uridylylation of GlnJ and GlnB.Considering that post-translational uridylylation of PII proteins modulates their signaling properties, a different requirement for divalent cations in the modification of GlnB and GlnJ adds an extra regulatory layer to the already intricate control of PII function.
authors: Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
authors: Pedro Filipe
authors: PF
authors: Teixeira
authors: Maria A
authors: MA
authors: Dominguez-Martin
authors: Stefan
authors: S
authors: Nordlund
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism*; D002413:Cations, Divalent / Q000378:metabolism*; D008274:Magnesium / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D051922:PII Nitrogen Regulatory Proteins / Q000378:metabolism*; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D012247:Rhodospirillum rubrum / Q000378:metabolism / Q000502:physiology*; D016415:Sequence Alignment; D015398:Signal Transduction
chemical_list: D001426:Bacterial Proteins; D002413:Cations, Divalent; C439048:GlnJ protein, Rhodospirillum rubrum; D051922:PII Nitrogen Regulatory Proteins; D008345:Manganese; C404143:PIID regulatory protein, Bacteria; D008274:Magnesium