Solid-state NMR spectra of lipid-anchored proteins under magic angle spinning

J Phys Chem B. 2014 Mar 6;118(9):2405-13. doi: 10.1021/jp4124106. Epub 2014 Feb 20.

Abstract

Solid-state NMR is a promising tool for elucidating membrane-related biological phenomena. We achieved the measurement of high-resolution solid-state NMR spectra for a lipid-anchored protein embedded in lipid bilayers under magic angle spinning (MAS). To date, solid-state NMR measurements of lipid-anchored proteins have not been accomplished due to the difficulty in supplying sufficient amount of stable isotope labeled samples in the overexpression of lipid-anchored proteins requiring complex posttranslational modification. We designed a pseudo lipid-anchored protein in which the protein component was expressed in E. coli and attached to a chemically synthesized lipid-anchor mimic. Using two types of membranes, liposomes and bicelles, we demonstrated different types of insertion procedures for lipid-anchored protein into membranes. In the liposome sample, we were able to observe the cross-polarization and the (13)C-(13)C chemical shift correlation spectra under MAS, indicating that the liposome sample can be used to analyze molecular interactions using dipolar-based NMR experiments. In contrast, the bicelle sample showed sufficient quality of spectra through scalar-based experiments. The relaxation times and protein-membrane interaction were capable of being analyzed in the bicelle sample. These results demonstrated the applicability of two types of sample system to elucidate the roles of lipid-anchors in regulating diverse biological phenomena.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon Isotopes / chemistry
  • Escherichia coli / metabolism
  • Isotope Labeling
  • Lipid Bilayers / chemistry
  • Lipid Bilayers / metabolism
  • Lipid-Linked Proteins / chemistry*
  • Lipid-Linked Proteins / metabolism
  • Liposomes / chemistry
  • Liposomes / metabolism
  • Nuclear Magnetic Resonance, Biomolecular*

Substances

  • Carbon Isotopes
  • Lipid Bilayers
  • Lipid-Linked Proteins
  • Liposomes