Use of Octyl β-Thioglucopyranoside in Two-Dimensional Crystallization of Membrane Proteins

Chami, Mohamed; Péhau‐Arnaudet, Gérard; Lambert, Olivier; Ranck, Jean-Luc; Lévy, Daniel; Rigaud, Jean‐Louis

doi:10.1006/jsbi.2001.4344

Cited by 26 publications

(22 citation statements)

References 41 publications

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“…Since the nature of the detergent is a crucial parameter for the result of two-dimensional crystallization trials (34,35), other detergents than the OG/cholate mixture were tried. For this purpose, the monomeric and dimeric LH1-RC-PufX bands purified in the OG/cholate sucrose gradient were dialyzed against buffers containing different detergents.…”

Section: Resultsmentioning

confidence: 99%

Structural Role of PufX in the Dimerization of the Photosynthetic Core Complex of Rhodobacter sphaeroides

Scheuring

Francia

Busselez

et al. 2004

Journal of Biological Chemistry

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119

142

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Monomeric and dimeric PufX-containing core complexes have been purified from membranes of wild-type Rhodobacter sphaeroides. Reconstitution of both samples by detergent removal in the presence of lipids leads to the formation of two-dimensional crystals constituted of dimeric core complexes. Two-dimensional crystals were further analyzed by cryoelectron microscopy and atomic force microscopy. A projection map at 26-Å resolution reveals that core complexes assemble in an "S"-shaped dimeric complex. Each core complex is composed of one reaction center, 12 light-harvesting 1 ␣/␤-heterodimers, and one PufX protein. The light-harvesting 1 assemblies are open with a gap of density of ϳ30-Å width and surround oriented reaction centers. A maximum density is found at the dimer junction. Based on the projection map, a model is proposed, in which the two PufX proteins are located at the dimer junction, consistent with the finding of dimerization of monomeric core complexes upon reconstitution. This localization of PufX in the core complex implies that PufX is the structural key for the dimer complex formation rather than a channel-forming protein for the exchange of ubiquinone/ubiquinol between the reaction center and the cytochrome bc1 complex.In purple photosynthetic bacteria, highly organized transmembrane pigment-protein complexes perform absorption of light and its conversion into chemical energy. Two light-harvesting complexes (LH), 1 LH2 and LH1, ensure the collection of light. Then the excitation energy is funneled toward the special pair of bacteriochlorophylls in the reaction center (RC), followed by an electron transfer from the special pair of bacteriochlorophylls to the ubiquinone (Q) acceptors Q A and Q B . After two photoreactions and proton captures, ubiquinol (QH 2 ) is formed at the Q B site that dissociates from the RC into the membrane. The bc 1 complex utilizes QH 2 and oxidized cytochrome c 2 as reductant and oxidant, respectively. The net result is a cyclic electron transfer that promotes the formation of a proton gradient across the membrane, which is utilized for ATP synthesis by F 1 F 0 -ATP synthase (for a review, see Ref. 1).The mechanisms of excitonic energy migration and photoinduced electron transfer have been studied in detail using biophysical approaches and analyzed at the molecular level following the resolution of the atomic structures of the RC (2), LH2 (3, 4), and the bc 1 complex (5). However, despite the wealth of information available on the individual proteins, their supramolecular organization in the membrane remains undetermined. A crucial issue is the spatial organization between LH1 and RC, forming the so-called core complex, in which the transformation of light energy into charge separation occurs. So far, no atomic model of the core complex is available. Early studies by various electron microscopy (EM) techniques of native membranes of Rhodopseudomonas viridis and Ectothiorhodospira halochloris have shown a single RC surrounded by a closed circle of light-harvesting molecule...

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Section: Resultsmentioning

confidence: 99%

Structural Role of PufX in the Dimerization of the Photosynthetic Core Complex of Rhodobacter sphaeroides

Scheuring

Francia

Busselez

et al. 2004

Journal of Biological Chemistry

Self Cite

119

142

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“…Since carbohydrates are readily available with various structural analogues and with both D-and L-enantiomers, combination with sugar head groups and hydrophobic alkyl chains would have a potential to construct a library of chiral surfactants. Although various thioglycosides have used for either solubilization membrane proteins or synthetic intermediates [22][23][24], few investigations have been performed to apply thioglycosides to MEKC analyses. Under this situation, we undertook to examine the applicability of thioglycosides to enantiomeric separation by MEKC.…”

Section: Introductionmentioning

confidence: 99%

Dodecyl thioglycopyranoside sulfates: Novel sugar‐based surfactants for enantiomeric separations by micellar electrokinetic capillary chromatography

et al. 2008

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Four novel chiral anionic surfactants having carbohydrate hydrophilic heads, sodium n-dodecyl 1-thio-beta-D-glucopyranoside 6-hydrogen sulfate (6-betaGlcD), sodium n-dodecyl 1-thio-beta-L-glucopyranoside 6-hydrogen sulfate (6-betaGlcL), sodium n-dodecyl 1-thio-beta-L-fucopyranoside 3-hydrogen sulfate (3-betaFucL), and sodium n-dodecyl 1-thio-alpha-L-rhamnopyranoside 3-hydrogen sulfate (3-alphaRhaL), were synthesized by selective sulfation of the corresponding thioglycosides. Their CMC determined by fluorescence using pyrene as a probe in water was 1.3-2.7 mM. These surfactants found to be useful as chiral selectors for enantiomeric separation by MEKC. The enantiomeric separation was optimized with respect to pH, buffer concentration, and surfactant concentration. Under the optimized conditions (50 mM phosphate buffer at pH 6.5, 30 mM surfactant, 20 kV), the enantiomeric separations of five dansylated amino acids (Dns-AAs) were achieved within approximately 20 min with the migration order of Val

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“…4 Moreover, recent investigations have pointed out the advantages of OTG against OG in several applications in the biomembrane field. 4,21,22 In many of the applications mentioned above, it is frequently the presence of electrolyte in the medium, and these substances may induce changes in both intramicellar and intermicellar interactions. 23 It is well-known that, in the case of nonionic surfactants, these interactions are relatively weak; however, they can modify both structural and dynamic properties of micelles, determining the behavior of the surfactant in a certain application.…”

Section: Introductionmentioning

confidence: 99%

Effect of NaCl on the Self-Aggregation of n-Octyl β-d-Thioglucopyranoside in Aqueous Medium

2006

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This report investigates the effect of sodium chloride (NaCl) on the micellization, surface activity, and the evolution in the shape and size of n-octyl -D-thioglucopyranoside (OTG) aggregates. By using surface tension measurements, information was obtained on both changes in the critical micelle concentration and adsorption behavior in the air-liquid interface with the electrolyte concentration. These data were used to obtain the thermodynamic properties of micellization along with the corresponding adsorption parameters in the airliquid interface. From extended static and dynamic light scattering measurements, the micelle molecular weight, the mean aggregation number, and the second virial coefficient, the apparent diffusion coefficient and the mean hydrodynamic radius of micelles in a range of NaCl concentrations were obtained. The light scattering data have shown that when the surfactant concentration is lower to 4.5 g/L, only spherical micelles are formed. However, an increase in the surfactant concentration induces an increase in micellar size, suggesting a rodlike growth of the micelles. This deviation of micelle geometry from spherical to rodlike is supported both by the ratio between the hydrodynamic radius and the radius of gyration and by the angular dependence of light scattering. On the other hand, the studies performed in the presence of high NaCl concentration (0.2 and 0.5 M) provide strong support for the view that the micelles may overlap together to form an entangled network above certain crossover concentration.

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Use of Octyl β-Thioglucopyranoside in Two-Dimensional Crystallization of Membrane Proteins

Cited by 26 publications

References 41 publications

Structural Role of PufX in the Dimerization of the Photosynthetic Core Complex of Rhodobacter sphaeroides

Structural Role of PufX in the Dimerization of the Photosynthetic Core Complex of Rhodobacter sphaeroides

Dodecyl thioglycopyranoside sulfates: Novel sugar‐based surfactants for enantiomeric separations by micellar electrokinetic capillary chromatography

Effect of NaCl on the Self-Aggregation of n-Octyl β-d-Thioglucopyranoside in Aqueous Medium

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