Combined use of 13C chemical shift and 1H alpha-13C alpha heteronuclear NOE data in monitoring a protein NMR structure refinement.

A large portion of the 13C resonance assignments for murine epidermal growth factor (mEGF) at pH 3.1 and 28 degrees C has been determined at natural isotope abundance. Sequence-specific 13C assignments are reported for 100% of the assignable C alpha, 96% of the C beta, 86% of the aromatic and 70% of the remaining peripheral aliphatic resonances of mEGF. A good correlation was observed between experimental and back-calculated C alpha chemical shifts for regions of regular beta-sheet structure. These assignments also provide the basis for interpreting 1H alpha-13C alpha heteronuclear NOE (HNOE) values in mEGF at natural isotope abundance. Some of the backbone polypeptide segments with high in…