Preferential Distribution of the Fluorescent Phospholipid Probes NBD-Phosphatidylcholine and Rhodamine-Phosphatidylethanolamine in the Exofacial Leaflet of Acetylcholine Receptor-Rich Membranes from Torpedo marmorata

Gutiérrez‐Merino, Carlos; Romanelli, Ida C. Bonini de; Pietrasanta, Lı́a I.; Barrantes, Francisco J.

doi:10.1021/bi00014a042

Cited by 26 publications

(18 citation statements)

References 58 publications

(68 reference statements)

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“…Approved therapeutic formulations include liposomal amphotericin B (AmBisome) for treating fungal infections,81 liposomal cytosine arabinoside (DepoCyt)82 for lymphomatous meningitis, liposomal verteporfin (Visudyne) for macular degeneration treatment,83 and liposomal doxorubicin (Myocet, Caelyx (DOXIL)) for breast and ovarian cancer,84 where the first indication for DOXIL was for the treatment of AIDS‐related Kaposi's sarcoma (KS). Advantages of liposome‐based nanomedicine templates include their non‐invasiveness for tissues and individual cells,85, 86 and that they are relatively nontoxic compared to polymeric nanoparticles 87. One disadvantage of liposomes is that due to the high curvature of the phospholipid bilayer in the small unilamillar vesicles (SUV), the liposomes are thermodynamically unstable and tend to fuse 87.…”

Section: Liposome‐based Nanomedicine Platformmentioning

confidence: 99%

Protein‐Based Nanomedicine Platforms for Drug Delivery

Maham

Tang

Wang

et al. 2009

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Protein-based nanomedicine platforms for drug delivery comprise naturally self-assembled protein subunits of the same protein or a combination of proteins making up a complete system. They are ideal for drug-delivery platforms due to their biocompatibility and biodegradability coupled with low toxicity. A variety of proteins have been used and characterized for drug-delivery systems, including the ferritin/apoferritin protein cage, plant-derived viral capsids, the small Heat shock protein (sHsp) cage, albumin, soy and whey protein, collagen, and gelatin. There are many different types and shapes that have been prepared to deliver drug molecules using protein-based platforms, including various protein cages, microspheres, nanoparticles, hydrogels, films, minirods, and minipellets. The protein cage is the most newly developed biomaterial for drug delivery and therapeutic applications. The uniform size, multifunctionality, and biodegradability push it to the frontier of drug delivery. In this Review, the recent strategic development of drug delivery is discussed with emphasis on polymer-based, especially protein-based, nanomedicine platforms for drug delivery. The advantages and disadvantages are also discussed for each type of protein-based drug-delivery system.

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Section: Liposome‐based Nanomedicine Platformmentioning

confidence: 99%

Protein‐Based Nanomedicine Platforms for Drug Delivery

Maham

Tang

Wang

et al. 2009

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462

375

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“…Specific activities in the order of 2.0 -2.8 nmol ␣-bungarotoxin sites/mg protein were obtained. The orientation of AChR in vesicles was measured as described by Hartig and Raftery (36) by determining the total toxinbinding sites in the presence of Triton X-100 and the right side out toxin-binding sites in the absence of detergent (36) as in previous work from our laboratory (37).…”

Section: Preparation Of Achr-rich Membranesmentioning

confidence: 99%

Unique Effects of Different Fatty Acid Species on the Physical Properties of the Torpedo Acetylcholine Receptor Membrane

Antollini

Barrantes

2002

Journal of Biological Chemistry

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To study the effects produced by free fatty acids (FFA) on the biophysical properties of Torpedo marmorata nicotinic acetylcholine receptor-rich native membranes and to investigate the topology of their binding site(s), fluorescence measurements were carried out using the fluorescent probe Laurdan (6-dodecanoyl-2-(dimethylamino) naphthalene) and ADIFAB, an Acrylodan-derivatized intestinal fatty acid-binding protein. The generalized polarization (GP) of the former probe was used to learn about the physical state of the membrane upon FFA binding. Saturated FFA induced a slight increase in GP, whereas cis-unsaturated fatty acids decreased GP. Double bond isomerism could also be distinguished; oleic acid (18:1cis) induced a net disordering effect, whereas elaidic acid (18:1trans) produced no changes in GP. The changes in the efficiency of the Fö rster energy transfer from the protein to Laurdan brought about by addition of FFA, together with the distances involved in this process, indicate that all FFA studied share a common site at the lipid-protein interface. However, despite being located at the same site, each class of FFA differs in its effect on the physical properties of the membrane. These data lead us to suggest that it is the direct action of FFA at the lipid-protein interface, displacing essential lipids from their sites rather than changes in bulk properties such as membrane fluidity that accounts for the effect of FFA on the acetylcholine receptor membrane.

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“…The analysis of the fluorescence energy transfer data, obtained by assessing the degree of donor (protein intrinsic fluorescence) quenching (see above), was carried out as indicated in Gutierrez-Merino et al (1994, 1995. The method was calibrated using experimental data for the fluorescein isothiocyanate-phosphatidylethanolamine/rhodamine-phosphatidylcholine and fluorescein isothiocyanate-phosphatidylethanolamine/XRITC-phosphatidylethanolamine donor/emission pairs and simulated using the data of Fung and Stryer (1978) for various other pairs.…”

Section: Analysis Of Forster Energy Transfer Datamentioning

confidence: 99%

Physical state of bulk and protein-associated lipid in nicotinic acetylcholine receptor-rich membrane studied by laurdan generalized polarization and fluorescence energy transfer

Antollini¹,

Soto²,

Romanelli³

et al. 1996

Biophysical Journal

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The spectral properties of the fluorescent probe laurdan (6-dodecanoyl-2-dimethylaminonaphthalene) were exploited to learn about the physical state of the lipids in the nicotinic acetylcholine receptor (AChR)-rich membrane and compare them with those in reconstituted liposomes prepared from lipids extracted from the native membrane and those formed with synthetic phosphatidylcholines. In all cases redshifts of 50 to 60 nm were observed as a function of temperature in the spectral emission maximum of laurdan embedded in these membranes. The so-called generalized polarization of laurdan exhibited high values (0.6 at 5 degrees C) in AChR-rich membranes, diminishing by approximately 85% as temperature increased, but no phase transitions with a clear Tm were observed. A still unexploited property of laurdan, namely its ability to act as a fluorescence energy transfer acceptor from tryptophan emission, has been used to measure properties of the protein-vicinal lipid. Energy transfer from the protein in the AChR-rich membrane to laurdan molecules could be observed upon excitation at 290 nm. The efficiency of this process was approximately 55% for 1 microM laurdan. A minimum donor-acceptor distance r of 14 +/- 1 A could be calculated considering a distance 0 < H < 10 A for the separation of the planes containing donor and acceptor molecules, respectively. This value of r corresponds closely to the diameter of the first-shell protein-associated lipid. A value of approximately 1 was calculated for Kr, the apparent dissociation constant of laurdan, indicating no preferential affinity for the protein-associated probe, i.e., random distribution in the membrane. From the spectral characteristics of laurdan in the native AChR-rich membrane, differences in the structural and dynamic properties of water penetration in the protein-vicinal and bulk bilayer lipid regions can be deduced. We conclude that 1) the physical state of the bulk lipid in the native AChR-rich membrane is similar to that of the total lipids reconstituted in liposomes, exhibiting a decreasing polarity and an increased solvent dipolar relaxation at the hydrophilic/hydrophobic interface upon increasing the temperature; 2) the wavelength dependence of laurdan generalized polarization spectra indicates the presence of a single, ordered (from the point of view of molecular axis rotation)-liquid (from the point of view of lateral diffusion) lipid phase in the native AChR membrane; 3) laurdan molecules within energy transfer distance of the protein sense protein-associated lipid, which differs structurally and dynamically from the bulk bilayer lipid in terms of polarity and molecular motion and is associated with a lower degree of water penetration.

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Preferential Distribution of the Fluorescent Phospholipid Probes NBD-Phosphatidylcholine and Rhodamine-Phosphatidylethanolamine in the Exofacial Leaflet of Acetylcholine Receptor-Rich Membranes from Torpedo marmorata

Cited by 26 publications

References 58 publications

Protein‐Based Nanomedicine Platforms for Drug Delivery

Protein‐Based Nanomedicine Platforms for Drug Delivery

Unique Effects of Different Fatty Acid Species on the Physical Properties of the Torpedo Acetylcholine Receptor Membrane

Physical state of bulk and protein-associated lipid in nicotinic acetylcholine receptor-rich membrane studied by laurdan generalized polarization and fluorescence energy transfer

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