Coupled ATPase-adenylate kinase activity in ABC transporters

Nat Commun. 2016 Dec 22:7:13864. doi: 10.1038/ncomms13864.

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 on 31P 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters / chemistry
  • ATP-Binding Cassette Transporters / genetics
  • ATP-Binding Cassette Transporters / metabolism*
  • Adenosine Triphosphatases / chemistry
  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism
  • Adenosine Triphosphate / metabolism
  • Adenylate Kinase / chemistry
  • Adenylate Kinase / genetics
  • Adenylate Kinase / metabolism
  • Amino Acid Substitution
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Binding Sites / genetics
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Humans
  • Magnetic Resonance Spectroscopy
  • Models, Biological
  • Models, Molecular
  • Mutagenesis, Site-Directed

Substances

  • ATP-Binding Cassette Transporters
  • Bacterial Proteins
  • Escherichia coli Proteins
  • MsbA protein, Bacteria
  • Adenosine Triphosphate
  • Adenylate Kinase
  • Adenosine Triphosphatases