In the present Communication we demonstrate the possibility to use high-resolution NMR for the investigation of membrane proteins in reconstituted high-density lipoprotein (rHDL) particles. The rHDL particles are nanoscale phospholipid bilayers wrapped around by a dimer of apolipoprotein A-1 (Bayburt, T. H.; Grinkova, Y. V.; Sligar, S. G. Nano Lett. 2002, 2, 853-856). In contrast to the commonly used spherical micelles, the rHDL particles incorporate a lipid bilayer like in biological membranes. These particles still undergo isotropic motion on the NMR time scale, providing the application of high-resolution NMR spectroscopy of the peptides and proteins embedded into their bilayer. As an example, the topology of the membrane-active peptide Antiamoebin-I in the bilayer of the rHDL particles was determined by using the lipid-soluble relaxation probe technique. Copyright © 2008 American Chemical Society.