ABSTRACT
Introduction Structural characterization of membrane proteins and many other biological systems by X-ray crystallography or solution NMR spectroscopy is di cult because of problems with crystallization, solubility or molecular size. Signicant advances, however, have been made to construct three-dimensional (3D) molecular structures from solid-state NMR data obtained under Magic Angle Spinning (MAS) [1] conditions[2], [3], [4]. ese eorts resulted in high-resolution 3D conformations for small peptides[5], [6], [7], [8] and the determination of medium-resolution backbone structures for a few solid-phase proteins.[9], [10], [11], [12].
