Probing Conformational Disorder in Neurotensin by Two-Dimensional Solid-State NMR and Comparison to Molecular Dynamics Simulations

An approach is introduced to characterize conformational ensembles of intrinsically unstructured peptides on the atomic level using two-dimensional solid-state NMR data and their combination with molecular dynamics simulations. For neurotensin, a peptide that binds with high affinity to a G-protein coupled receptor, this method permits the investigation of the changes in conformational preferences of a neurotransmitter transferred from a frozen aqueous solution via a lipid model phase to the receptor-bound form. The results speak against a conformational preorganization of the ligand in detergents in which the receptor has been shown to be functional. Further extensions to the study of protein folding are possible.