Fatty acid binding sites of human and bovine albumins: Differences observed by spin probe ESR

Muravsky, Vladimir; Gurachevskaya, Tatjana; Berezenko, Stephen; Schnurr, Kerstin; Gurachevsky, Andrey

doi:10.1016/j.saa.2009.05.003

Cited by 20 publications

(27 citation statements)

References 19 publications

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“…Compared to data previously reported 11,26 on the interaction between the 5-doxyl stearic spin probe and albumins, which showed that this spin probe has a restricted motion in the protein complex, our data suggest that CAT16 in the BSA complex is characterized by higher mobility. Considering that (a) albumin has several binding sites for hydrophobic molecules and (b) CAT16 and 5-doxyl stearic acid have different hydrophobicities, it could be assumed that their binding is different.…”

Section: ■ Results and Discussioncontrasting

confidence: 77%

EPR and Circular Dichroism Solution Studies on the Interactions of Bovine Serum Albumin with Ionic Surfactants and β-Cyclodextrin

et al. 2012

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The interactions of bovine serum albumin (BSA) with ionic surfactants (sodium dodecyl sulfate, SDS, and cetyltrimethylammonium bromide, CTAB) and β-cyclodextrin (β-CD) have been investigated by electron paramagnetic resonance (EPR) and circular dichroism measurements. The spin probe selected to report on the interaction of albumin with surfactants and/or β-CD was 4-N,N-dimethyl hexadecyl ammonium-2,2,6,6-tetramethylpiperidine-1-oxyl iodide (CAT16), on account of (a) its balance between electrostatic and hydrophobic character and (b) the ability of BSA to form complexes with various organic molecules. The distribution of the spin probe among different environments in solutions containing only BSA was confirmed by the existence of two components in the EPR spectra: one revealing a restricted mobility of the spin probe, attributed to the protein-spin probe complex, and another one showing free movement, attributed to the spin probe in solution. The presence of surfactants and/or β-CD alters the distribution of CAT16 between various compartments in each system. Formation of protein aggregates as a result of thermal denaturation was evidenced by the appearance of an immobilized component in the EPR spectrum. This component is not present in the EPR spectra of CAT16 in protein/surfactant or protein/cyclodextrin solutions. Circular dichroism spectra of BSA provided information about changes in the secondary structure of the protein induced by the presence of surfactants and/or cyclodextrin in solution. The results demonstrate that β-CD hinders the interaction between the employed surfactants and the protein. The cationic surfactant (CTAB) induces changes in protein conformation at a lower concentration compared to the anionic surfactant (SDS).

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Section: ■ Results and Discussioncontrasting

confidence: 77%

EPR and Circular Dichroism Solution Studies on the Interactions of Bovine Serum Albumin with Ionic Surfactants and β-Cyclodextrin

et al. 2012

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“…In order to expand this established EPR spectroscopic viewpoint from 5-MSL HSA, the next sections of this study proceed with an approach elucidating pH-dependent protein-ligand interactions in spin probed HSA samples. Here, the pH-dependent self-assembly properties of HSA with the spin probes 5-DSA and 16-DSA [42] are tested thoroughly. The spectral features of pH-denatured albumin samples are investigated on an empirical level as it will be shown in the following.…”

Section: Cw Epr and Ansmentioning

confidence: 99%

“…16-DSA [42] are tested thoroughly. The spectral features of pH-denatured albumin samples are investigated on an empirical level as it will be shown in the following.…”

Section: Cw Eprmentioning

confidence: 99%

“…The reported pKa value is usually in the range of 4.5-4.9 for the carboxyl group of stearic acids [104][105][106][107]. Due to the complex spectral composition consisting of the fractions a, b 1 , b 2 and f throughout most pH regimes [42,110], an alternative strategy is now rationalized that allows for extracting useful information from these datasets. For example, a comparison of Figure 3b,c reveals that aggregate formation (red) is significantly hampered by adding only one instead of two molar equivalents of 16-DSA.…”

Section: Cw Eprmentioning

confidence: 99%

“…Here, the protein phase space [38] of HSA is explored in a very broad pH range from at least pH 1 to 12, mainly using spin-labeled fatty acids (FA) for monitoring the proteins solution properties. This spin probing approach allows to observe phenomena as ligand binding capabilities, rotational dynamics or changes in local polarity in continuous wave (CW) EPR [39][40][41][42][43]. Complementary nanoscale distance measurements with four-pulse double electron-electron resonance (DEER) reveal the solution structure [44][45][46][47] and may therefore also indirectly display functional changes in the solution shape of albumin from the viewpoint of spatial rearrangements of paramagnetic centers in EPR-active, albumin-bound FAs from the protein interior (5-DSA) or its surface [48][49][50].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Exploring the pH-Induced Functional Phase Space of Human Serum Albumin by EPR Spectroscopy

et al. 2018

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A systematic study on the self-assembled solution system of human serum albumin (HSA) and paramagnetic doxyl stearic acid (5-DSA and 16-DSA) ligands is reported covering the broad pH range 0.7–12.9, mainly using electron paramagnetic resonance (EPR) methods. It is tested to which extent the pH-induced conformational isomers of HSA reveal themselves in continuous wave (CW) EPR spectra from this spin probing approach in comparison to an established spin-labeling strategy utilizing 3-maleimido proxyl (5-MSL). Most analyses are conducted on empirical levels with robust strategies that allow for the detection of dynamic changes of ligand, as well as protein. Special emphasis has been placed on the EPR spectroscopic detection of a molten globule (MG) state of HSA that is typically found by the fluorescent probe 8-Anilino- naphthalene-1-sulfonic acid (ANS). Moreover, four-pulse double electron-electron resonance (DEER) experiments are conducted and substantiated with dynamic light scattering (DLS) data to determine changes in the solution shape of HSA with pH. All results are ultimately combined in a detailed scheme that describes the pH-induced functional phase space of HSA.

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Maleimido-proxyl as an EPR spin label for the evaluation of conformational changes of albumin

et al. 2017

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Albumin is the most abundant plasma protein and as such has been the subject of many studies using a variety of techniques. One of them, capable of monitoring the conformational changes and the binding capacity of proteins, is electron paramagnetic resonance spectroscopy (EPR) spin labeling. To date, albumin has been investigated using a number of different spin labels, mostly spin-labeled fatty acids (SLFAs). However, albumin can bind up to seven equivalents of fatty acids, making it difficult to determine which parts of the molecule undergo conformational changes. To obtain information from a specific site on a protein, spin labels that bind to free cysteine residues may be used. In this work, the applicability of such a label, 3-maleimido proxyl (5-MSL), was evaluated for monitoring conformational changes of bovine serum albumin (BSA) at different temperatures and pH values. Also, the effect of ethanol, reactive oxygen species (hydrogen peroxide and superoxide radical), and the binding of ligands specific for albumin, namely fatty acids, and several drugs were evaluated. The results indicate that the labeling of albumin at its free cysteine residue (Cys-34) using 5-MSL may successfully be used for the detection of conformational changes, even in the case of the subtle alterations induced by ligand binding.

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Fatty acid binding sites of human and bovine albumins: Differences observed by spin probe ESR

Cited by 20 publications

References 19 publications

EPR and Circular Dichroism Solution Studies on the Interactions of Bovine Serum Albumin with Ionic Surfactants and β-Cyclodextrin

EPR and Circular Dichroism Solution Studies on the Interactions of Bovine Serum Albumin with Ionic Surfactants and β-Cyclodextrin

Exploring the pH-Induced Functional Phase Space of Human Serum Albumin by EPR Spectroscopy

Maleimido-proxyl as an EPR spin label for the evaluation of conformational changes of albumin

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