The residence times of molecular complexes in solution are important for understanding biomolecular functions and drug actions. We show that NMR data of intermolecular hydrogen-bond scalar couplings can yield information on the residence times of molecular complexes in solution. The molecular exchange of binding partners via the breakage and reformation of a complex causes self-decoupling of intermolecular hydrogen-bond scalar couplings, and this self-decoupling effect depends on the residence time of the complex. For protein-DNA complexes, we investigated the salt concentration dependence of intermolecular hydrogen-bond scalar couplings between the protein side-chain 15N and DNA phosphate 31P nuclei, from which the residence times were analyzed. The results were consistent with those obtained by 15Nz-exchange spectroscopy. This self-decoupling-based kinetic analysis is unique in that it does not require any different signatures for the states involved in the exchange, whereas such conditions are crucial for kinetic analyses by typical NMR and other methods.
ASJC Scopus subject areas
- Materials Science(all)
- Physical and Theoretical Chemistry