Dissociation of ATP-binding cassette nucleotide-binding domain dimers into monomers during the hydrolysis cycle

J Biol Chem. 2012 Apr 27;287(18):14994-5000. doi: 10.1074/jbc.M112.340281. Epub 2012 Mar 8.


ATP-binding cassette (ABC) proteins have two nucleotide-binding domains (NBDs) that work as dimers to bind and hydrolyze ATP, but the molecular mechanism of nucleotide hydrolysis is controversial. In particular, it is still unresolved whether hydrolysis leads to dissociation of the ATP-induced dimers or opening of the dimers, with the NBDs remaining in contact during the hydrolysis cycle. We studied a prototypical ABC NBD, the Methanococcus jannaschii MJ0796, using spectroscopic techniques. We show that fluorescence from a tryptophan positioned at the dimer interface and luminescence resonance energy transfer between probes reacted with single-cysteine mutants can be used to follow NBD association/dissociation in real time. The intermonomer distances calculated from luminescence resonance energy transfer data indicate that the NBDs separate completely following ATP hydrolysis, instead of opening. The results support ABC protein NBD association/dissociation, as opposed to constant-contact models.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters / chemistry*
  • ATP-Binding Cassette Transporters / genetics
  • Adenosine Triphosphate / chemistry*
  • Adenosine Triphosphate / genetics
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Binding Sites
  • Escherichia coli / enzymology
  • Escherichia coli / genetics
  • Hydrolysis
  • Methanococcus / enzymology*
  • Methanococcus / genetics
  • Models, Molecular*
  • Protein Multimerization*


  • ATP-Binding Cassette Transporters
  • Bacterial Proteins
  • Adenosine Triphosphate