The neutron small-angle camera D11 at the high-flux reactor, Grenoble

Ibel, K.

doi:10.1107/s0021889876011394

Cited by 417 publications

(149 citation statements)

References 9 publications

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“…All experiments have been performed with the D ll camera at the high flux reactor in Grenoble (Ibel, 1976). Details of such measurements were as described by May et al (1982).…”

Section: Methodsmentioning

confidence: 99%

Incoherent scattering corrections for forward scattering of neutrons by aqueous buffers. Temperature dependence and influence of absorbing salts

Knoll¹,

Schmidt²,

Ibel³

1985

J Appl Cryst

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Following the procedure suggested by May, Ibel & Haas [J. Appl. Cryst. (1982), 15, 15-19] for the correlation of transmission data with the level of neutrons scattered incoherently into the full solid angle 4n measurements have been made of the transmission and incoherent scattering intensities of aqueous buffers of different HEO/D20 ratios at temperatures between 280 and 343 K. That it is possible to extend the proposed calibration procedure to absorbing-ions-containing buffers is also shown.

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“…All experiments have been performed with the D ll camera at the high flux reactor in Grenoble (Ibel, 1976). Details of such measurements were as described by May et al (1982).…”

Section: Methodsmentioning

confidence: 99%

Incoherent scattering corrections for forward scattering of neutrons by aqueous buffers. Temperature dependence and influence of absorbing salts

Knoll¹,

Schmidt²,

Ibel³

1985

J Appl Cryst

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“…Earlier neutron scattering studies on LDL [52 -541 had utilised Guinier analyses using the neutron instrument D11 [39]. Fig.…”

Section: Nutive Ldlmentioning

confidence: 99%

“…[39]) at the high-flux neutron reactor at the Institut-LaueLangevin, Grenoble. All samples were freshly prepared and were exhaustively dialysed for 30 h at 4 T against glucosefree X-ray buffer (see above) in 100% 2 H 2 0 with four changes of buffer to remove H 2 0 .…”

Section: Neutron Solution Scuttrringmentioning

confidence: 99%

Structural changes in oxidised low‐density lipoproteins and of the effect of the anti‐atherosclerotic drug probucol observed by synchrotron X‐ray and neutron solution scattering

Bellamy

Nealis

Aitken

et al. 1989

European Journal of Biochemistry

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The atherosclerotic properties of low-density lipoproteins (LDL) are thought to be strongly enhanced by oxidation. The lipid-lowering drug probucol reduces the susceptibility of LDL to oxidation. Synchrotron X-ray and high-flux neutron solution scattering curves were used to characterise the structural properties of human LDL, before and after modification by oxidation with CuZt and the addition of probucol, in order to evaluate these techniques. Analyses based on Guinier plots, simple two-shell spherical modelling, and the use of cubic splines and indirect transformation show that a 20-h incubation with Cu2+ ions (but not 6 h) causes some of the LDL to associate to form larger aggregated particles. Gel electrophoresis on Cu2+-oxidised LDL shows a concomitant degradation of the apolipoprotein B-100 as well as the formation of high molecular mass forms. These experiments indicate that the apoprotein B-100 structure has been significantly disrupted by oxidation. The addition of probucol to LDL causes an increase in the polydispersity of LDL, as evidenced by small changes in the Guinier curves and some weakening of the minima in the X-ray scattering curves. N o changes in the quasispherical shape of LDL are observed and gel electrophoresis indicates no changes. It is possible that probucol may exert its effect by increasing the range of sizes of LDL and that the lipid-lowering effect of probucol in vivo might be caused by the preferential catabolism of the higher molecular mass forms of LDL thus created.Cardiovascular disease is implicated in half of all deaths in industrialised countries. Epidemiological studies show a strong positive correlation between elevated plasma concentrations of low-density lipoproteins (LDL) cholesterol and the risk of premature coronary heart disease [l, 21. The role of LDL is to deliver cholesterol to body tissues which require it for membrane synthesis and steroid hormone production [3]. LDL is distinguishable from all other lipoprotein classes in plasma by its high relative proportion of cholesteryl ester and the presence of a single apolipoprotein (apo) B-100. LDL has a simple quasi-spherical particle symmetry of outer diameter 21 -25 nm, as determined by electron microscopy and solution scattering [4 -81. It is composed of one molecule of apo B-100 with a 4% (by mass) oligosaccharide content (Table 1) and its binding to lipid can be likened to its insertion into a lipid vesicle [8 -121. Compositional studies show that LDL is 77% (by mass) lipid. There are about 2900 lipid molecules (Table l), primarily cholesteryl linoleate and triacylglycerol in the core, surrounded by a monolayer of polar phospholipids and cholesterol. Secondary structure predictions, circular dichroism and Fourier-transform infrared (FT-IR) spectroscopy show that apo B-100 is approximately 40% cc-helix, 25% fl-sheet and 35% random coil in its main chain conformation [9, 11, 13 - B-100 are found at the N-terminus, this part is presumed to constitute a globular structure.The presence of lipid-laden foam cells is a...

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“…Neutron experiments were carried out on instrument D 17 at the high-flux reactor at the Institut Laue-Langevin, Grenoble, which can be compared to instrument D11 [36]. For Guinier region work, the sample-to-detector distance was 2.70-2.88 m and 3.46 m, which were used respectively with wavelengths of 1.374 -1.384 nm and 1.088 nm (wavelength spread A i / A of 10%).…”

Section: X-ray and Neutron Scattering Measurementsmentioning

confidence: 99%

Molecular modelling of human complement component C3 and its fragments by solution scattering

Perkins¹,

1986

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Solution scattering experiments using both X-rays and neutrons are reported for human complement component C 3 and up to six other glycoprotein fragments that are derived from C3. The X-ray and neutron molecular masses and neutron matchpoints are in agreement with the known primary sequence of C 3. The X-ray radius of gyration RG of C3 is 5.2 nm and is similar for the related forms C~U , C3(a+ b) and C3 b. The X-ray cross-sectional radius of gyration Rxs of C3b is however less than that of C3, C3u and C3(a+b). The major fragments of C3b, namely C3c and C3dg, were studied. The Ro of C3c is 4.7 nm and for C3dg is 2.9 nm. C3c and C 3dg do not interact when they coexist in solution in equimolar amounts. When C 3u is cleaved into iC 3u, the RG of iC3u increases to 5.9 nm and its Rxs decreases, showing that C3c and C3dg behave as independent entities within the parent glycoprotein. Analyses of the neutron RG and Rxs values by contrast variation techniques confirm the X-ray analyses, and show no evidence for significant hydrophobic or hydrophilic domains within C3 or any of its fragments. Shape analyses show that C3, C3c and C3dg are elongated particles. Debye models were developed using the scattering curve out to Q = 1.6 nm-I . These show that C 3 and C 3c resemble oblate ellipsoids while C3dg resembles a prolate ellipsoid. C3dg lies on the long edge of C3c within C3. The dimensions of the modelsare 18 nmx 2 nm x 10 nmforC3,18 nmx 2 nm x 7 nmforC3cand 10 nm x 2 nm x 3 nm forC3dg. These models are compatible with analyses of the scattering curve RG and Rxs values, data from sedimentation coefficients, and images of C 3 and C 3c seen by electron microscopy.

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The neutron small-angle camera D11 at the high-flux reactor, Grenoble

Cited by 417 publications

References 9 publications

Incoherent scattering corrections for forward scattering of neutrons by aqueous buffers. Temperature dependence and influence of absorbing salts

Incoherent scattering corrections for forward scattering of neutrons by aqueous buffers. Temperature dependence and influence of absorbing salts

Structural changes in oxidised low‐density lipoproteins and of the effect of the anti‐atherosclerotic drug probucol observed by synchrotron X‐ray and neutron solution scattering

Molecular modelling of human complement component C3 and its fragments by solution scattering

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