Probing exchange kinetics and atomic resolution dynamics in high-molecular-weight complexes using dark-state exchange saturation transfer NMR spectroscopy

Nat Protoc. 2012 Jul 19;7(8):1523-33. doi: 10.1038/nprot.2012.077.


We present the protocol for the measurement and analysis of dark-state exchange saturation transfer (DEST), a novel solution NMR method for characterizing, at atomic resolution, the interaction between an NMR-'visible' free species and an NMR-'invisible' species transiently bound to a very high-molecular-weight (>1 MDa) macromolecular entity. The reduced rate of reorientational motion in the bound state that precludes characterization by traditional NMR methods permits the observation of DEST. (15)N-DEST profiles are measured on a sample comprising the dark state in exchange with an NMR-visible species; in addition, the difference (ΔR(2)) in (15)N transverse relaxation rates between this sample and a control sample comprising only the NMR-visible species is also obtained. The (15)N-DEST and ΔR(2) data for all residues are then fitted simultaneously to the McConnell equations for various exchange models describing the residue-specific dynamics in the bound state(s) and the interconversion rate constants. Although the length of the experiments depends strongly on sample conditions, approximately 1 week of NMR spectrometer time was sufficient for full characterization of samples of amyloid-β (Aβ) at concentrations of ~100 μM.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Amyloid beta-Peptides / chemistry
  • Kinetics
  • Macromolecular Substances / chemistry*
  • Molecular Weight
  • Nitrogen Isotopes
  • Nuclear Magnetic Resonance, Biomolecular / methods*
  • Software
  • Time Factors


  • Amyloid beta-Peptides
  • Macromolecular Substances
  • Nitrogen Isotopes