Novel Chelate-Induced Magnetic Alignment of Biological Membranes

Prosser, R. Scott; Volkov, V. B.; Shiyanovskaya, Irina

doi:10.1016/s0006-3495(98)77659-3

Cited by 79 publications

(83 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, if ⌬ is negative for the first group of lanthanide compounds, ⌬ is positive for the second group and vice versa. All experimental results obtained for lanthanide-containing liquid crystals 13,14 and for phospholipid bilayers [15][16][17][18][19] doped with lanthanide chelates are in agreement with a negative ⌬ value for the first group and a positive ⌬ value for the second group. But as we will show further in this paper, the reverse situation can be expected too.…”

Section: Introductionsupporting

confidence: 80%

On the magnetic anisotropy of lanthanide-containing metallomesogens

Mironov

Galyametdinov

Ceulemans

et al. 2000

The Journal of Chemical Physics

View full text Add to dashboard Cite

A general theoretical model of the origin of the magnetic anisotropy in paramagnetic metal-containing liquid crystals is developed. General relations between the molecular magnetic anisotropy of mesogenic lanthanide complexes and the macroscopic magnetic anisotropy of these liquid crystals in the mesophase are obtained. The net magnetic anisotropy of a real metallomesogen is shown to be the result of a complex interplay between the molecular magnetic anisotropy, orientation of the long molecular axis, and disorder effects. The sign of the magnetic anisotropy ⌬ depends not only on the anisotropy of the tensor of molecular magnetic susceptibility, but also on the orientation of the long molecular axis of rodlike lanthanide complexes with respect to the principal magnetic axes of the molecular tensor of magnetic susceptibility. The influence of microand macroscopic disorder in real liquid crystals is discussed. Numerical parametric calculations were used to rationalize the variation of the magnitude and sign of the magnetic anisotropy in a series of isostructural lanthanide-containing metallomesogens. Experimental magnetic susceptibility and magnetic anisotropy of a series of ͓Ln͑LH͒ 3 ͑NO 3 ͒ 3 ͔ compounds ͑LH is a Schiff base͒ are well reproduced by calculations based on the present model. Limitations of the Bleaney theory of magnetic anisotropy are analyzed.

show abstract

Section: Introductionsupporting

confidence: 80%

On the magnetic anisotropy of lanthanide-containing metallomesogens

Mironov

Galyametdinov

Ceulemans

et al. 2000

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…This has been shown to significantly reduce paramagnetic broadening and prevent direct association of peptides with the lanthanide ions. More specifically, a phospholipid chelate complexed with ytterbium (DMPE-DTPA: Yb 3ϩ ) has been shown to be readily incorporated into bicelles (99). This has been demonstrated with gramicidin A for which the 2 H NMR spectra of 2 H exchange-labeled peptide indicate that the chelate sequesters the lanthanides away from the peptide binding sites (99).…”

Section: Study Of Peptides In Lanthanide-doped Bicellesmentioning

confidence: 99%

Bicelles as model membranes for solid‐ and solution‐state NMR studies of membrane peptides and proteins

Marcotte

Auger

2005

Concepts Magnetic Resonance

190

196

View full text Add to dashboard Cite

ABSTRACT:Bicelles are an attractive membrane mimetic system because of their planar surface and lipid composition, which resemble biological membranes. In addition, their orientation and morphologic properties make them amenable to solid-and solution-state NMR. This article reviews the physical properties of bicelles, such as magnetic alignment and viscosity as well as the different models proposed in the literature to explain the bicelle morphology. The utility of bicelles for studying the interaction and structure of membrane peptides and proteins by solid-and solution-state NMR is also presented, along with the advantages and limitations of bicelles.

show abstract

“…16 Conversely, the addition of paramagnetic lanthanide ions with a large positive magnetic susceptibility anisotropy tensor (Eu 3+ , Er 3+ , Tm 3+ and Yb 3+ ) changes Δχ to a positive value; thus, causing the bicelles to flip 90°such that the membrane normal is parallel with the direction of the static magnetic field. 16,19,20 The aim of this research is to develop a new structural biology technique for determining the topology of integral membrane proteins inserted into magnetically aligned phospholipid bilayers utilizing spin-labeled EPR spectroscopy. In order to demonstrate the feasibility of this technique, we have used the nicotinic acetylcholine receptor (AChR).…”

Section: Introductionmentioning

confidence: 99%

Determining the Topology of Integral Membrane Peptides Using EPR Spectroscopy

et al. 2006

View full text Add to dashboard Cite

This paper reports on the development of a new structural biology technique for determining the membrane topology of an integral membrane protein inserted into magnetically aligned phospholipid bilayers (bicelles) using EPR spectroscopy. The nitroxide spin probe, 2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid (TOAC) was attached to the pore-lining transmembrane domain (M2δ) of the nicotinic acetylcholine receptor (AChR) and incorporated into a bicelle. The corresponding EPR spectra revealed hyperfine splittings that were highly dependent on the macroscopic orientation of the bicelles with respect to the static magnetic field. The helical tilt of the peptide can be easily calculated using the hyperfine splittings gleaned from the orientational dependent EPR spectra. A helical tilt of 14° was calculated for the M2δ peptide with respect to the bilayer normal of the membrane, which agrees well with previous 15 N solid-state NMR studies. The helical tilt of the peptide was verified by simulating the corresponding EPR spectra using the standardized MOMD approach. This new method is advantageous because: (1) bicelle samples are easy to prepare, (2) the helical tilt can be directly calculated from the orientational-dependent hyperfine splitting in the EPR spectra, and (3) EPR spectroscopy is approximately 1000 fold more sensitive than 15 N solid-state NMR spectroscopy; thus, the helical tilt of an integral membrane peptide can be determined with only 100 μg of peptide. The helical tilt can be determined more accurately by placing TOAC spin labels at several positions with this technique.

show abstract

Novel Chelate-Induced Magnetic Alignment of Biological Membranes

Cited by 79 publications

References 34 publications

On the magnetic anisotropy of lanthanide-containing metallomesogens

On the magnetic anisotropy of lanthanide-containing metallomesogens

Bicelles as model membranes for solid‐ and solution‐state NMR studies of membrane peptides and proteins

Determining the Topology of Integral Membrane Peptides Using EPR Spectroscopy

Contact Info

Product

Resources

About