Small‐angle neutron scattering study of the structure of protein / detergent complexes

Guo, Xuan-Hui; Zhao, Nanming; Chen, S. H.; Teixeira, J.

doi:10.1002/bip.360290206

Cited by 172 publications

(132 citation statements)

References 17 publications

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“…and can be obtained from the Fourier transform of equation (1) (Chen & Teixeira, 1986;Guo et al, 1990), where R is the radius of the primary particles. The modulus of the scattering vector Q = (4 / ) sin( /2) is defined by the scattering angle , and the wavelength of the X-rays .…”

Section: Saxs Modelmentioning

confidence: 99%

Fractal aggregates of the Pt nanoparticles synthesized by the polyol process and poly(N-vinyl-2-pyrrolidone) reduction

Lin

Jeng

et al. 2007

J Appl Cryst

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Small-angle X-ray scattering was used to characterize the size and aggregation behavior of the Pt nanoparticles synthesized by the polyol process and the unusual poly(N-vinyl-2-pyrrolidone) (PVP) reduction. With formaldehyde (HCHO) as the reduction agent, the Pt nanoparticles synthesized in aqueous solutions with a high PVP/PtCl 4 weight ratio were characterized by short rods with a 70% polydispersity in rod length. The size and size distribution of the rodlike Pt nanoparticles (3 nm in rod length and 2 nm in rod diameter) are consistent with the corresponding transmission electron microscopy image. With a comparable PVP/PtCl 4 weight ratio in the aqueous solution containing HCHO, the high number density of reduced Pt nanoparticles led to a fractal-like aggregation with a fractal dimension of 2.1 and a correlation length of~30 nm. We also demonstrated that Pt nanoparticles can be synthesized by PVP reduction at 323 K without HCHO. The particle size and the clustering behavior of the Pt nanoparticles reduced by PVP are closely related to the PVP concentration in the solution. Both the Pt nanoparticles synthesized in the commonly used polyol process and the unusual PVP reduction form fractal-like clusters via the PVP-metal nanoparticle association when the number density of the Pt nanoparticles in the solutions is high.

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Section: Saxs Modelmentioning

confidence: 99%

Fractal aggregates of the Pt nanoparticles synthesized by the polyol process and poly(N-vinyl-2-pyrrolidone) reduction

Lin

Jeng

et al. 2007

J Appl Cryst

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“…Information concerning the structure of protein-surfactant complexes has been derived from rheological (Reynolds and Tanford 1970b), spectroscopic (Das et al 1998;Gelamo et al 2002), electrophoretic (Gelamo et al 2002), binding (Jones 1975;Tanford 1980), and scattering studies (Chen and Teixeira 1986;Guo et al 1990). Several models have been proposed for the structure of protein-surfactant complexes in SDS over its critical micelle concentration (CMC): (1) a correlated "necklace and bead" model in which clusters with a micelle-like structure are stabilized by protein ( Fig.…”

mentioning

confidence: 99%

“…Several models have been proposed for the structure of protein-surfactant complexes in SDS over its critical micelle concentration (CMC): (1) a correlated "necklace and bead" model in which clusters with a micelle-like structure are stabilized by protein ( Fig. 1; Shirahama et al 1974;Guo et al 1990;Turro et al 1995); (2) "rod-like" prolate elliposidal surfactant aggregate with a semi-minor axis of ∼18 Å, corresponding to the surfactant chain length (Reynolds and Tanford 1970b;Tanford 1980); and (3) a flexible capped helical cylinder micelle with the protein wrapping around the micelle (Lundahl et al 1986). A small-angle neutron scattering study of BSA and ovalbumin complexes with SDS led to the conclusion that a necklace and bead structure, composed of protein-surfactant aggregates, accounted for the scattering behavior of these systems (Chen and Teixeira 1986;Guo et al 1990), which was confirmed by NMR experiments by Turro et al (1995).…”

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confidence: 99%

Effect of sodium dodecyl sulfate on folding and thermal stability of acid‐denatured cytochrome c: A spectroscopic approach

Keiderling

2004

Protein Science

102

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The molten globule (MG) state can be an intermediate in the protein folding pathway; thus, its detailed description can help understanding protein folding. Sodium dodecyl sulfate (SDS), an anionic surfactant that is commonly used to mimic hydrophobic binding environments such as cell membranes, is known to denature some native state proteins, including horse cytochrome c (cyt c). In this article, refolding of acid denatured cyt c is studied under the influence of SDS to form MG-like states at both low concentration and above the critical micelle concentration using Fourier transform Infrared (FTIR) and ultraviolet and visible absorption as well as fluorescence and circular dichroism (CD). Thermal denaturation monitored with FTIR and CD shows distinct final high temperature states starting from MG-like states formed with different SDS/protein ratios. The results suggest that the SDS/protein ratio as well as the actual SDS (or protein) concentration affects structure and its thermal stability. Thermal denaturation monitored with CD and FTIR for cyt c at neutral pH but denatured with SDS showed that at a high SDS/protein ratio, the thermal behavior of MG-like states formed at low and neutral pH are quite similar. Based on the results obtained, the merits of two models of the protein-surfactant structure are discussed for different SDS concentrations.

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“…The structure of protein-surfactant complexes has been studied for many years using several low molecular mass globular proteins such as bovine serum albumin, lysozyme, and others by means of several spectroscopic techniques such as UV-visible absorption (5), fluorescence and circular dichroism (12,(15)(16)(17), small angle neutron scattering (18,19), small angle x-ray scattering (SAXS) (20), light scattering (21), and other tensiometric and viscosimetric physicochemical techniques (22) as well as isothermal titration calorimetry and differential scanning calorimetry (23,24).…”

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confidence: 99%

Small Angle X-ray Scattering (SAXS) Study of the Extracellular Hemoglobin of Glossoscolex paulistus

Gelamo

Itri

Tabak

2004

Journal of Biological Chemistry

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pH effects on the oligomeric structure of giant Glossoscolex paulistus extracellular hemoglobin in the oxyand met-forms have been studied as well as effects of the addition of anionic sodium dodecyl sulfate surfactant. A radius of gyration of 110 Å is observed for a macromolecule. At 2 mM surfactant, the radius of gyration diminishes slightly for the oxy-form. However, the extrapolated initial scattering intensity (I(0)) decreases a factor of 2.5, indicating protein dissociation. At 20 mM surfactant, further I(0) decrease is observed, with a reduction of radius of gyration to approximately 30 Å consistent with dissociation into smaller subunits. At pH 9.0, the scattering curves are similar to that obtained for the protein in the presence of 20 mM surfactant at pH 7.0. A radius of gyration of approximately 35 Å shows that the giant hemoglobin dissociation into small subunits also occurs at alkaline pH. From the I(0) value, one can suggest that the tetramer is the main scatter at pH 9.0. At pH 7.0, the met-form dissociates to a larger extent at 2 mM surfactant as compared with the oxy-form, and the main scatters seem to be the 1/12 subunit. At pH 9.0, for the oxy-form, the addition of surfactant does not modify the scattering curve and a radius of gyration approximately 30 Å is obtained, while for the met-form some kind of aggregation is observed. Our results give support to conclude that the iron oxidation state is an important factor modulating the oligomeric dissociation.Annelid extracellular hemoglobins are giant molecules that have a characteristic hexagonal bilayer appearence in electron micrographs, high cooperativity of oxygen binding, and low iron and heme contents (1-4). The hemoglobin of the earthworm Lumbricus terrestris (HbLt) 1 is the most extensively studied annelid hemoglobin. It consists of about 180 polypeptide chains in an arrangement of two heme-containing subunits (monomer M and disulfide-bonded trimer T) and non-globin linker subunits with molecular masses in the range 24 -32 kDa. A model of quaternary structure (bracelet model) explains the properties and subunit structure of HbLt: three copies of monomer subunit and three copies of the trimer subunit form a dodecamer subunit, (abcd) 3 of about 200 kDa. Twelve such complexes of heme-containing chains are linked together by 36 heme-deficient linker chains to provide the total mass of about 3500 kDa. The 1/12 subunit of the whole protein is associated then to (abc) 3 d 3 L 3 , where L stands for the linker chains. Since 1996 a significant effort has been devoted by several laboratories to elucidate in more detail the arrangements between the subunits from the structural point of view to better understand the oxygenation of this giant hemoglobin. The three most important contributions in this research are associated with the mass spectrometry determination of the molecular masses of all subunits (3), to the three-dimensional reconstructions at a low resolution of 35 Å obtained by cryoelectron microscopy (1) and which were able to give results o...

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Small‐angle neutron scattering study of the structure of protein / detergent complexes

Cited by 172 publications

References 17 publications

Fractal aggregates of the Pt nanoparticles synthesized by the polyol process and poly(N-vinyl-2-pyrrolidone) reduction

Fractal aggregates of the Pt nanoparticles synthesized by the polyol process and poly(N-vinyl-2-pyrrolidone) reduction

Effect of sodium dodecyl sulfate on folding and thermal stability of acid‐denatured cytochrome c: A spectroscopic approach

Small Angle X-ray Scattering (SAXS) Study of the Extracellular Hemoglobin of Glossoscolex paulistus

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