title: In vitro interaction between the ammonium transport protein AmtB and partially uridylylated forms of the P(II) protein GlnZ.
abstract: The ammonium transport family Amt/Rh comprises ubiquitous integral membrane proteins that facilitate ammonium movement across biological membranes. Besides their role in transport, Amt proteins also play a role in sensing the levels of ammonium in the environment, a process that depends on complex formation with cytosolic proteins of the P(II) family. Trimeric P(II) proteins from a variety of organisms undergo a cycle of reversible posttranslational modification according to the prevailing nitrogen supply. In proteobacteria, P(II) proteins are subjected to reversible uridylylation of each monomer. In this study we used the purified proteins from Azospirillum brasilense to analyze the effect of P(II) uridylylation on the protein's ability to engage complex formation with AmtB in vitro. Our results show that partially uridylylated P(II) trimers can interact with AmtB in vitro, the implication of this finding in the regulation of nitrogen metabolism is discussed. We also report an improved expression and purification protocol for the A. brasilense AmtB protein that might be applicable to AmtB proteins from other organisms.
authors.affiliation: Department of Biochemistry and Molecular Biology, Universidade Federal do Parana, Curitiba, Brazil.
authors.forename: Thiago E
authors.initials: TE
authors.lastname: Rodrigues
authors.forename: Victor E P
authors.initials: VE
authors.lastname: Souza
authors.forename: Rose A
authors.initials: RA
authors.lastname: Monteiro
authors.forename: Edileusa C M
authors.initials: EC
authors.lastname: Gerhardt
authors.forename: Luíza M
authors.initials: LM
authors.lastname: Araújo
authors.forename: Leda S
authors.initials: LS
authors.lastname: Chubatsu
authors.forename: Emanuel M
authors.initials: EM
authors.lastname: Souza
authors.forename: Fábio O
authors.initials: FO
authors.lastname: Pedrosa
authors.forename: Luciano F
authors.initials: LF
authors.lastname: Huergo
mesh_terms: D015806:Azospirillum brasilense / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D027682:Cation Transport Proteins / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D009584:Nitrogen / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D014542:Uridine Monophosphate / Q000737:chemistry
chemical_list: C111096:AmtB protein, E coli; D001426:Bacterial Proteins; D027682:Cation Transport Proteins; D029968:Escherichia coli Proteins; C100965:GlnZ protein, Azospirillum brasilense; D000644:Quaternary Ammonium Compounds; D014542:Uridine Monophosphate; D009584:Nitrogen