COMPLETE RESOLUTION OF THE SOLID-STATE NMR-SPECTRUM OF A UNIFORMLY N-15-LABELED MEMBRANE-PROTEIN IN PHOSPHOLIPID-BILAYERS

Complete resolution of the amide resonances in a three-dimensional sol id-state NMR correlation spectrum of a uniformly N-15-labeled membrane protein in oriented phospholipid bilayers is demonstrated, The three orientationally dependent frequencies, H-1 chemical shift, H-1-N-15 di polar coupling, and N-15 chemical shift, associated with each amide re sonance are responsible for resolution among resonances and provide su fficient angular restrictions for protein structure determination, Bec ause the protein is completely immobilized by the phospholipids on the relevant NMR time scales (10 kHz), the linewidths will not degrade in the spectra of larger proteins, Therefore, these results demonstrate that solid-state NMR experiments can overcome the correlation time pro blem and extend the range of proteins that can have their structures d etermined by NMR spectroscopy to include uniformly N-15-labeled membra ne proteins in phospholipid bilayers.