High resolution 1H NMR of a lipid cubic phase using a solution NMR probe

Boyle-Roden, Elizabeth; Hoefer, Nicole; Dey, Krishna Kishor; Grandinetti, Philip J.; Caffrey, Martin

doi:10.1016/j.jmr.2007.08.010

Cited by 20 publications

(17 citation statements)

References 36 publications

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“…67 Various spectroscopic methods used depending on the specific application are Fourier transform infra-red spectroscopy (FTIR) 68 and nuclear magnetic resonance (NMR). [69][70][71][72][73][74] Light scattering techniques provide dimensional information in the case of dispersed phases. It is even possible to measure concentrated and turbid systems using advanced light scattering tools.…”

Section: Discrete Micellar Phasesmentioning

confidence: 99%

“…192 Diffusion through the continuous lipid film was studied for many different molecules using NMR and other techniques. 70,[193][194][195] The cubic phases could be implemented in the controlled release applications for a range of water soluble or membrane anchored molecules that include small organic molecules or larger molecules like peptides and proteins and also for nuclear DNA. 196 Crystallization of proteins has emerged as one of the important tools for the success of crystallography in determining the structures of soluble and subsequently membrane proteins.…”

Section: Biological Molecules: Proteins Membrane Proteins and Dnamentioning

confidence: 99%

See 1 more Smart Citation

Monoolein: a magic lipid?

Kulkarni

Wachter

Iglesias

et al. 2011

Phys. Chem. Chem. Phys.

401

403

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During the last few years, there has been an extraordinary increase in publications describing the manifold applications of monoolein, one of the most important lipids in the fields of drug delivery, emulsion stabilization and protein crystallization. In this perspective we present a comprehensive review of the phase behavior of this 'magic lipid'. An account of various mesophases formed in the presence of water and a collection of formulae for the calculation of their nano-structural parameters are provided. Effects of chemical and biological molecules including lipids, detergents, salts, sugars, proteins and DNA on the classical behavior are also discussed. Physicochemical triggers such as, temperature, pressure and shearing modulate the phase behavior of monoolein self assemblies that are covered in subsequent sections. Finally the growing applications of monoolein in various fields are also reported.

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Section: Discrete Micellar Phasesmentioning

confidence: 99%

Section: Biological Molecules: Proteins Membrane Proteins and Dnamentioning

confidence: 99%

Monoolein: a magic lipid?

Kulkarni

Wachter

Iglesias

et al. 2011

Phys. Chem. Chem. Phys.

401

403

View full text Add to dashboard Cite

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“…This reorientation of lipid molecules on the NMR timescale leads to averaging of the anisotropic components of the NMR signal that are responsible for broadening of peaks in anisotropic lipid phases (e.g., lamellar or hexagonal phases). Therefore, it is possible to acquire almost liquid-like spectra of the lipid components of LCP in terms of line-width and intensity, and the NMR spectra of LCP samples have even been recorded in a solution state probe (20), although we observed that high resolution-magic angle spinning (HR-MAS) improves resolution. NMR methods that rely on parameters accessible in isotropic systems, such as polarization transfer rates (21), relaxation times (22), and line-shapes (23) have also been applied successfully in LCP.…”

Section: Introductionmentioning

confidence: 98%

Two Classes of Cholesterol Binding Sites for the β 2 AR Revealed by Thermostability and NMR

Gater

Saurel

Iordanov

et al. 2014

Biophysical Journal

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Cholesterol binding to G protein-coupled receptors (GPCRs) and modulation of their activities in membranes is a fundamental issue for understanding their function. Despite the identification of cholesterol binding sites in high-resolution x-ray structures of the ?2 adrenergic receptor (β2AR) and other GPCRs, the binding affinity of cholesterol for this receptor and exchange rates between the free and bound cholesterol remain unknown. In this study we report the existence of two classes of cholesterol binding sites in β2AR. By analyzing the β2AR unfolding temperature in lipidic cubic phase (LCP) as a function of cholesterol concentration we observed high-affinity cooperative binding of cholesterol with sub-nM affinity constant. In contrast, saturation transfer difference (STD) NMR experiments revealed the existence of a second class of cholesterol binding sites, in fast exchange on the STD NMR timescale. Titration of the STD signal as a function of cholesterol concentration provided a lower limit of 100 mM for their dissociation constant. However, these binding sites are specific for both cholesterol and β2AR, as shown with control experiments using ergosterol and a control membrane protein (KpOmpA). We postulate that this specificity is mediated by the high-affinity bound cholesterol molecules and propose the formation of transient cholesterol clusters around the high-affinity binding sites.

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“…Small-angle X-ray diffraction has been the principal tool employed in the characterization of LCPs, particularly in mapping out the temperature–composition phase diagrams in lipid–water systems . Nuclear magnetic resonance (NMR) techniques, both solution and solid state, have also been applied to LCPs and related systems with both one-dimensional (1D) 1 H and 13 C as well as some two-dimensional (2D) homonuclear spectra reported. − Furthermore, pulsed-field gradient NMR (PFG-NMR) has been utilized to probe translational diffusion properties within the water channels and the lipid bilayer of LCPs, and release profiles of encapsulated hydrophilic molecules. ,− More recently 1 H– 15 N heteronuclear NMR spectra of a small water-soluble protein encapsulated in LCP have been reported, which demonstrates the potential use of LCPs as an alternative to reverse micelle encapsulation for protein hydration studies …”

Section: Introductionmentioning

confidence: 99%

Physiochemical Characterization and Stability of Lipidic Cubic Phases by Solution NMR

et al. 2020

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Lipidic inverse bicontinuous cubic phases (LCPs), formed via the spontaneous self-assembly of lipids such as monoolein, have found increasing applications in the stabilization and crystallization of integral membrane proteins for structural characterization using X-ray crystallography. Their use as effective drug release matrices has also been demonstrated. Nuclear magnetic resonance (NMR) spectroscopy, both solution and solid state, has previously been employed for the characterization of LCPs and related systems. Herein, we report a number of novel features of solution NMR for probing the fundamental composition and structural properties of monoolein-based LCPs. These include (1) more complete assignments of both 1 H and 13 C chemical shifts, (2) direct quantification of hydration level in LCPs using one-dimensional (1D) 1 H NMR, and (3) monitoring longer-term stability of LCPs and evaluating alterations introduced into standard LCPs at the submolecular level.

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High resolution 1H NMR of a lipid cubic phase using a solution NMR probe

Cited by 20 publications

References 36 publications

Monoolein: a magic lipid?

Monoolein: a magic lipid?

Two Classes of Cholesterol Binding Sites for the β 2 AR Revealed by Thermostability and NMR

Physiochemical Characterization and Stability of Lipidic Cubic Phases by Solution NMR

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