Investigating fatty acids inserted into magnetically aligned phospholipid bilayers using EPR and solid-state NMR spectroscopy

Nusair, Nisreen A.; Tiburu, Elvis K.; Dave, Paresh C.; Lorigan, Gary A.

doi:10.1016/j.jmr.2004.03.004

Cited by 12 publications

(10 citation statements)

References 56 publications

(134 reference statements)

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“…The results demonstrate that decanoic acid interacts with the lipid acyl chains at both pH 4.4 and pH 7.4. This result is consistent with our previous studies, [31] as well as the results of fatty acids in lipid membranes reported by others. [34] …”

Section: Resultssupporting

confidence: 94%

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Solid‐state NMR spectroscopic studies on the interaction of sorbic acid with phospholipid membranes at different pH levels

Chu

Hawes

Lorigan

2009

Magnetic Reson in Chemistry

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2H, 31P, and 1H-magic-angle-spinning (MAS) solid-state NMR spectroscopic methods were used to elucidate the interaction between sorbic acid, a widely used weak acid food preservative, and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) bilayers under both acidic and neutral pH conditions. The linewidth broadening observed in the 31P NMR powder pattern spectra and the changes in the 31P longitudinal relaxation time (T1) indicate interaction with the phospholipid headgroup upon titration of sorbic acid or decanoic acid into DMPC bilayers over the pH range from 3.0 to 7.4. The peak intensities of sorbic acid decrease upon addition of paramagnetic Mn2+ ions in DMPC bilayers as recorded in the 1H MAS NMR spectra, suggesting that sorbic acid molecules are in close proximity with the membrane/aqueous surface. No significant 2H quadrupolar splitting (Δ γQ) changes are observed in the 2H NMR spectra of DMPC-d54 upon titration of sorbic acid, and the change of pH has a slight effect on Δ γQ, indicating that sorbic acid has weak influence on the orientation order of the DMPC acyl chains in the fluid phase over the pH range from 3.0 to 7.4. This finding is in contrast to the results of the decanoic acid/DMPC-d54 systems, where Δ γQ increases as the concentration of decanoic acid increases. Thus, in the membrane association process, sorbic acids are most likely interacting with the headgroups and shallowly embedded near the top of the phospholipid headgroups, rather than inserting deep into the acyl chains. Thus, antimicrobial mode of action for sorbic acid may be different from that of long-chain fatty acids.

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Section: Resultssupporting

confidence: 94%

“…[31] In this study, the effects of sorbic acid on well-defined 1,2-dimyristoyl- sn -glycero-3-phosphocholine (DMPC, Fig. 1C) model membranes were investigated at different pH levels with 2 H, 31 P, and 1 H-MAS NMR spectroscopic methods.…”

Section: Introductionmentioning

confidence: 99%

Solid‐state NMR spectroscopic studies on the interaction of sorbic acid with phospholipid membranes at different pH levels

Chu

Hawes

Lorigan

2009

Magnetic Reson in Chemistry

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“…About 4% of ethanol is bound to the membrane; the lifetime of ethanol association is on the order of a few nanoseconds. Structural and dynamic properties of stearic acid- d 35 in bicelles containing cholesterol have been studied by 2 H NMR [220] and later compared to EPR results [221]. Two cannabinoids were investigated in the presence of oriented bicelles [222].…”

Section: Interaction Of Small Molecules With Bicellesmentioning

confidence: 99%

When detergent meets bilayer: Birth and coming of age of lipid bicelles

Dürr

Soong

Ramamoorthy

2013

Progress in Nuclear Magnetic Resonance Spectroscopy

119

108

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“…1 Synthetic lipids with a nitroxide or with a fluorescent probe have been extensively used in the past decades as useful molecular tools in ESR and fluorescence spectroscopy for studying the structure and function of complex systems such as phospholipid bilayers and membranes. [2][3][4] Until now, various spin-labeled analogues of naturally occurring lipids have been synthesized with a nitroxide radical either on the polar head-group or on the acyl chains. 5,6 The interaction of fatty acid spin labels with membrane components reflects the structure and function of the local environment with a high degree of sensitivity to motion and molecular rotation within the membrane organization.…”

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confidence: 99%

“…5,6 The interaction of fatty acid spin labels with membrane components reflects the structure and function of the local environment with a high degree of sensitivity to motion and molecular rotation within the membrane organization. 3 Paramagnetic fatty acids have been used to study bilirubin-phospholipid interactions, 7 binding properties of bovine b-lactoglobulin 8 and oxidative membrane damage. 9 Lipophilic nitroxides can prevent peroxide-induced oxidative stress and apoptosis as shown with mitochondriatargeted nitroxides.…”

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Synthesis of New Paramagnetic Fatty Acids and Lipophilic Spin Labels

Balog

Abé

Kálai³

et al. 2007

Synthesis

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Starting from readily available five-membered cyclic nitrones, paramagnetic analogues of palmitic and hexadec-2E-enoic acids are described with a range of pyrrolidine ring orientations. Herein we report the synthesis of 3,4-disubstituted lipophilic pyrroline nitroxides through a palladium-catalyzed cross-coupling reaction. Lipophilic phosphonium salt and SH-specific labels (methanethiosulfonates and isoselenuronium salts) with allylic and propargylic terminal groups are also described.It was the widespread occurrence of lipids as fuel molecules, signal molecules and membrane components that directed the researchers' attention to this field. 1 Synthetic lipids with a nitroxide or with a fluorescent probe have been extensively used in the past decades as useful molecular tools in ESR and fluorescence spectroscopy for studying the structure and function of complex systems such as phospholipid bilayers and membranes. 2-4 Until now, various spin-labeled analogues of naturally occurring lipids have been synthesized with a nitroxide radical either on the polar head-group or on the acyl chains. 5,6 The interaction of fatty acid spin labels with membrane components reflects the structure and function of the local environment with a high degree of sensitivity to motion and molecular rotation within the membrane organization. 3 Paramagnetic fatty acids have been used to study bilirubin-phospholipid interactions, 7 binding properties of bovine b-lactoglobulin 8 and oxidative membrane damage. 9 Lipophilic nitroxides can prevent peroxide-induced oxidative stress and apoptosis as shown with mitochondriatargeted nitroxides. 10 These potential applications have inspired researchers to synthesize a range of paramagnetically modified fatty acids for more than 40 years. The most simple and widely used approach is the synthesis of DOXYL fatty acids [e.g. 2-(3-carboxyethyl-4,4-dimethyl-2-dodecyl-3-oxyl)oxazolidine radical] using fatty acid ketoesters and 2-amino-2-methylpropanol as starting materials. 6 However, these compounds have limited stability toward reduction and protonation on the ring. To eliminate this problem we have reported the synthesis of more stable pyrrolidine (proxyl and azetoxyl) based fatty acids, starting from lipophilic nitrones, through a Grignard reaction of an unsaturated w-bromo alkene, followed by oxidation of the terminal double bond. 11 Synthesis of 3,4-disubstituted pyrroline nitroxide based fatty acids and oxa-oleic acid was also reported. 12In this paper we report the synthesis of novel 2,2-and 2,5-disubstituted pyrrolidine nitroxide fatty acids using a Grignard reaction, and 3,4-disubstituted pyrroline nitroxide fatty acids through a Suzuki reaction. Such compounds were also converted to their thiolspecific reagents and membrane probes. Treatment of 5,5-dimethyl-1-pyrroline N-oxide (DMPO; 1) or 2,5-dimethyl-1-pyrroline Noxide 13 (7) with dodecylmagnesium bromide in diethyl ether, yielded the trisubstituted nitrones 2 and 8, respectively, after oxidation of the resulting hydroxylamines to the nitrones ...

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Investigating fatty acids inserted into magnetically aligned phospholipid bilayers using EPR and solid-state NMR spectroscopy

Cited by 12 publications

References 56 publications

Solid‐state NMR spectroscopic studies on the interaction of sorbic acid with phospholipid membranes at different pH levels

Solid‐state NMR spectroscopic studies on the interaction of sorbic acid with phospholipid membranes at different pH levels

When detergent meets bilayer: Birth and coming of age of lipid bicelles

Synthesis of New Paramagnetic Fatty Acids and Lipophilic Spin Labels

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