title: Coupled ATPase-adenylate kinase activity in ABC transporters.
abstract: ATP-binding cassette (ABC) transporters, a superfamily of integral membrane proteins, catalyse the translocation of substrates across the cellular membrane by ATP hydrolysis. Here we demonstrate by nucleotide turnover and binding studies based on31P solid-state NMR spectroscopy that the ABC exporter and lipid A flippase MsbA can couple ATP hydrolysis to an adenylate kinase activity, where ADP is converted into AMP and ATP. Single-point mutations reveal that both ATPase and adenylate kinase mechanisms are associated with the same conserved motifs of the nucleotide-binding domain. Based on these results, we propose a model for the coupled ATPase-adenylate kinase mechanism, involving the canonical and an additional nucleotide-binding site. We extend these findings to other prokaryotic ABC exporters, namely LmrA and TmrAB, suggesting that the coupled activities are a general feature of ABC exporters.
authors.affiliation: Institute for Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe-University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany.
authors.forename: Hundeep
authors.initials: H
authors.lastname: Kaur
authors.affiliation: Institute for Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe-University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lakatos-Karoly
authors.affiliation: Institute for Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe-University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany.
authors.forename: Ramona
authors.initials: R
authors.lastname: Vogel
authors.affiliation: Institute for Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Nöll
authors.affiliation: Institute for Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Tampé
authors.affiliation: Institute for Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe-University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Glaubitz
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000263:Adenylate Kinase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C079726:MsbA protein, Bacteria; D000255:Adenosine Triphosphate; D000263:Adenylate Kinase; D000251:Adenosine Triphosphatases