Structural studies of α-bungarotoxin. 2. 1H NMR assignments via an improved relayed coherence transfer nuclear Overhauser enhancement experiment

Complete sequence-specific assignments of the 1H NMR spectrum of bungarotoxin were reported in a previous paper. The assignment was significantly aided by the use of the homonuclear Hartman-Hahn relayed coherence transfer nuclear Overhauser enhancement spectroscopy experiment (HRNOESY) which we present here, as a modification of relayed coherence transfer nuclear Overhauser enhancement spectroscopy (relayed NOESY). As shown here, HRNOESY resolves problems of proton resonance overlap especially in extended chain conformations as found in β-sheets