Lipid-protein nanodiscs: possible application in high-resolution NMR investigations of membrane proteins and membrane-active peptides

Biochemistry (Mosc). 2009 Jul;74(7):756-65. doi: 10.1134/s0006297909070086.

Abstract

High-resolution NMR is shown to be applicable for investigation of membrane proteins and membrane-active peptides embedded into lipid-protein nanodiscs (LPNs). (15)N-Labeled K+-channel from Streptomyces lividans (KcsA) and the antibiotic antiamoebin I from Emericellopsis minima (Aam-I) were embedded in LPNs of different lipid composition. Formation of stable complexes undergoing isotropic motion in solution was confirmed by size-exclusion chromatography and (31)P-NMR spectroscopy. The 2D 1H-(15)N-correlation spectra were recorded for KcsA in the complex with LPN containing DMPC and for Aam-I in LPNs based on DOPG, DLPC, DMPC, and POPC. The spectra recorded were compared with those in detergent-containing micelles and small bicelles commonly used in high-resolution NMR spectroscopy of membrane proteins. The spectra recorded in LPN environments demonstrated similar signal dispersion but significantly increased (1)H(N) line width. The spectra of Aam-I embedded in LPNs containing phosphatidylcholine showed significant selective line broadening, thus suggesting exchange process(es) between several membrane-bound states of the peptide. (15)N relaxation rates were measured to obtain the effective rotational correlation time of the Aam-I molecule. The obtained value (approximately 40 nsec at 45 degrees C) is indicative of additional peptide motions within the Aam-I/LPN complex.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Hypocreales / chemistry
  • Lipids / chemistry*
  • Magnetic Resonance Spectroscopy / methods*
  • Membrane Proteins / chemistry*
  • Nanostructures / chemistry*
  • Peptaibols
  • Peptides / chemistry*
  • Potassium Channels / chemistry*

Substances

  • Bacterial Proteins
  • Lipids
  • Membrane Proteins
  • Peptaibols
  • Peptides
  • Potassium Channels
  • prokaryotic potassium channel
  • antiamoebin