METHODS FOR MEASUREMENT OF INTERMOLECULAR NOES BY MULTINUCLEAR NMR-SPECTROSCOPY - APPLICATION TO A BACTERIOPHAGE-LAMBDA N-PEPTIDE BOXB RNA COMPLEX/

New pulse schemes for recording intermolecular NOEs in a molecular com plex consisting of N-15, C-13 labeled and unlabeled components are pre sented. The pulse sequences select for magnetization transferred from protons on the unlabeled component to proximal protons of the labeled molecule. Filtering (suppression of signal from C-13 labeled molecules ) is accomplished using adiabatic C-13 inversion pulses which are swep t at a rate which is tuned according to the one-bond H-1-C-13 scalar c oupling vs carbon chemical shift profile of the labeled molecule in th e complex. Significantly improved spectra are obtained relative to dat a recorded with other purging schemes: Improvements are demonstrated i n experiments where intermolecular NOEs between labeled RNA-unlabeled peptide and labeled protein-unlabeled peptide are recorded. A discussi on of structural information obtained for a complex of the amino-termi nal arginine rich domain of the N protein from bacteriophage lambda an d boxB RNA using the new methodology is presented.