An evaluation of detergents for NMR structural studies of membrane proteins

J Biomol NMR. 2004 Jan;28(1):43-57. doi: 10.1023/B:JNMR.0000012875.80898.8f.

Abstract

Structural information on membrane proteins lags far behind that on soluble proteins, in large part due to difficulties producing homogeneous, stable, structurally relevant samples in a membrane-like environment. In this study 25 membrane mimetics were screened using 2D (1)H-(15)N heteronuclear single quantum correlation NMR experiments to establish sample homogeneity and predict fitness for structure determination. A single detergent, 1-palmitoyl-2-hydroxy-sn-glycero-3-[phospho-RAC-(1-glycerol)] (LPPG), yielded high quality NMR spectra with sample lifetimes greater than one month for the five proteins tested - R. sphaeroides LH1 alpha and beta subunits, E. coli and B. pseudofirmus OF4 ATP synthase c subunits, and S. aureus small multidrug resistance transporter - with 1, 2, or 4 membrane spanning alpha-helices, respectively. Site-specific spin labeling established interhelical distances in the drug transporter and genetically fused dimers of c subunits in LPPG consistent with in vivo distances. Optical spectroscopy showed that LH1 beta subunits form native-like complexes with bacteriochlorophyll a in LPPG. All the protein/micelle complexes were estimated to exceed 100 kDaltons by translational diffusion measurements. However, analysis of (15)N transverse, longitudinal and (15)N[(1)H] nuclear Overhauser effect relaxation measurements yielded overall rotational correlation times of 8 to 12 nsec, similar to a 15-20 kDalton protein tumbling isotropically in solution, and consistent with the high quality NMR data observed.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antiporters / chemistry
  • Antiporters / pharmacology
  • Detergents / chemistry*
  • Detergents / pharmacology
  • Escherichia coli Proteins
  • Glycerides / chemistry*
  • Glycerides / pharmacology
  • Membrane Proteins / chemistry*
  • Membrane Proteins / drug effects
  • Membrane Proteins / pharmacology
  • Micelles
  • Mitochondrial Proton-Translocating ATPases / chemistry
  • Mitochondrial Proton-Translocating ATPases / drug effects
  • Nuclear Magnetic Resonance, Biomolecular*
  • Protein Folding
  • Proton-Translocating ATPases / chemistry
  • Spin Labels

Substances

  • 1-palmitoyl-2-hydroxy-sn-glycero-3-(phospho-RAC-(1-glycerol))
  • Antiporters
  • Detergents
  • Escherichia coli Proteins
  • Glycerides
  • Membrane Proteins
  • Micelles
  • Spin Labels
  • EmrE protein, E coli
  • mitochondrial ATPase subunit c
  • Mitochondrial Proton-Translocating ATPases
  • Proton-Translocating ATPases