Influence of Conterions on the Radius of Gyration of Phenylalanine Specific Transfer RNA as Determined by Small Angle X-Ray Studies

1971 ◽  
Vol 18 (3) ◽  
pp. 436-441 ◽  
Author(s):  
Ingrid Pilz ◽  
Otto Kratky ◽  
Friedrich Haar ◽  
Freidrich Cramer
Keyword(s):  
Small Angle ◽  
Transfer Rna ◽  
Radius Of Gyration ◽  
X Ray

Information retrieval from X-ray small-angle scattering with polychromatic (`white') synchrotron radiation

1983 ◽  
Vol 16 (1) ◽  
pp. 42-46 ◽  
Author(s):  
O. Glatter ◽  
P. Laggner
Keyword(s):  
Synchrotron Radiation ◽  
Small Angle ◽  
Particle Shape ◽  
Structural Information ◽  
Small Angle Scattering ◽  
Radius Of Gyration ◽  
X Ray ◽  
Angle Scattering ◽  
Slit Length ◽  
Hinge Bending

The possibilities of obtaining structural information from X-ray small-angle scattering experiments with `white' polychromatic synchrotron radiation using line collimation are investigated by numerical simulation. Theoretical scattering curves of geometrical models were smeared with the appropriate wavelength distributions and slit-length functions, afflicted by statistical noise, and then evaluated by identical methods as normally used for experimental data, as described previously [program ITP; Glatter (1977). J. Appl. Cryst. 10, 415–421]. It is shown that even for a wavelength distribution of 50% half width, the information content is not limited to the parameters derived from the central part of the scattering curves, i.e. the radius of gyration and the zero-angle intensity, but also allows qualitative information on particle shape via the distance distribution function p(r). By a `hinge-bending model' consisting of two cylinders linked together at different angles it is demonstrated that changes in the radius of gyration amounting to less than 5% can be detected and quantified, and the qualitative changes in particle shape be reproduced.

Phenylalanyl-tRNA Synthetase from Baker'Yeast: Structural Organization of the Enzyme and Its Complex with tRNAPhe as Determined by X-Ray Small-Angle Scattering

1979 ◽  
Vol 34 (1-2) ◽  
pp. 20-26 ◽  
Author(s):  
Ingrid Pilz ◽  
Karin Goral ◽  
Friedrich v. d. Haar
Keyword(s):  
Molecular Weight ◽  
Small Angle ◽  
Quaternary Structure ◽  
Trna Synthetase ◽  
Distribution Functions ◽  
Maximum Diameter ◽  
Radius Of Gyration ◽  
X Ray ◽  
Angle Scattering ◽  
The Difference

Abstract The quaternary structure of the phenylalanyl-tRNA synthetase and its complex with tRNAPhe was studied in dilute solutions by small angle X-ray scattering. For the free synthetase the radius of gyration was determined as 5.5 nm, the volume 523 nm3, the maximum diameter 17.5 nm and the molecular weight as 260 000 using an isopotential specific volume of 0.735. The overall shape could be best approximated by a flat cylinder with dimensions 18.2 nm X 11.5 nm X 4 nm ; the loose structure was approximated by building up the cylinder by spheres (diameter 4.2 nm).The corresponding parameters of the enzyme tRNA complex were the following: radius of gyration 5.9 nm, volume 543 nm 3, maximum diameter 21 nm and molecular weight 290 000. These parameters suggest an 1:1 complex, whereby it must be assumed that the tRNA molecule is attached in the extension of the longer axis. From the difference in the distance distribution functions of the free enzyme and the complex it is evident that we have to assume a change of conformation (contraction) of the enzyme upon the binding of the specific tRNA.

Calcium-induced increase in the radius of gyration and maximum dimension of calmodulin measured by small-angle x-ray scattering

Biochemistry ◽  
1985 ◽  
Vol 24 (24) ◽  
pp. 6740-6743 ◽  
Author(s):  
B. A. Seaton ◽  
J. F. Head ◽  
D. M. Engelman ◽  
F. M. Richards
Keyword(s):  
Small Angle ◽  
Radius Of Gyration ◽  
Maximum Dimension ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

ULTRA SMALL-ANGLE X-RAY SCATTERING STUDY OF FLOCCULATION IN SILICA-FILLED RUBBER

2014 ◽  
Vol 87 (2) ◽  
pp. 348-359 ◽  
Author(s):  
Satoshi Mihara ◽  
Rabin N. Datta ◽  
Wilma K. Dierkes ◽  
Jacques W. M. Noordermeer ◽  
Naoya Amino ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Small Angle ◽  
Radius Of Gyration ◽  
X Ray ◽  
X Ray Scattering ◽  
Mass Fractal ◽  
Mass Fractal Dimension ◽  
Lower Mobility ◽  
Low Mass ◽  
Ray Scattering

ABSTRACT The flocculation of silica during vulcanization is monitored using the ultra small-angle X-ray scattering technique for two different types of silica: a highly dispersible silica (HD) and a conventional silica (CV), mixed into a blend of S-SBR and BR rubbers. The cutoff length of the silica aggregate Rss and the mass fractal dimension Dm, which indicate the degree of flocculation of aggregates, are estimated according to the modified unified equation. The aggregate radius Ra is estimated to be related to the lower cutoff length Rss, indicating the radius of gyration of the mass-fractal structure. For both silicas, Ra increases during vulcanization. For the CV silica, an increase of Dm is observed, whereas no significant increase of Dm can be seen for the HD silica. The Ra of CV is relatively high compared with that of HD. On the other hand, the CV silica shows a relatively lower Dm compared with that of HD. These results indicate that CV has a larger size of aggregates and lower degree of agglomeration of its aggregates. The presence of di(tri-ethoxy-silyl-propyl)tetrasulfide (TESPT) as coupling agent between the silica and rubber decreases the aggregate radius of silica. However, in the absence of TESPT, a low mass-fractal dimension, which means a low degree of agglomeration of aggregates, is observed. This results from a lower mobility of silica aggregates, depending on the size of the aggregates. The silica loading also has an influence on the flocculation process. The aggregate radius increases as the silica loading is increased. At the same time, a higher mass-fractal dimension, and therefore also a higher degree of agglomeration, can be seen at higher silica loading.

Investigation of Ribulose-1,5-bisphosphate Carboxylase-Oxygenase from Tobacco by Small Angle X-Ray Scattering: A Structural Model for the Enzyme in Solution

1988 ◽  
Vol 43 (5-6) ◽  
pp. 373-376 ◽  
Author(s):  
P. M. Abuja ◽  
I. Pilz
Keyword(s):  
Small Angle ◽  
Quaternary Structure ◽  
Higher Plants ◽  
Maximum Diameter ◽  
Radius Of Gyration ◽  
Bisphosphate Carboxylase ◽  
X Ray ◽  
X Ray Scattering ◽  
Inactive Form ◽  
Ray Scattering

The quaternary structure of ribulose-1,5-bisphosphate carboxylase/oxygenase from tobacco (Nicotiana tabacum) was investigated in solution by means of small angle X-ray scattering. The most important molecular parameters as the radius of gyration (Rg) and the maximum diameter (Dmax) were determined. Both the active and the inactive form of the enzyme were measured at 5 °C and at 20 °C. A more distinct difference in size could be detected between the inactive forms at these two temperatures (Rg = 4.80 nm (5 °C) and 4.68 nm (20 °C)) than between the active forms (Rg = 4.73 nm and 4.69 nm). The maximum diameters were determined to be 13.1 nm for the inactive form at 5 °C and 12.8 nm for the other forms. A model is proposed consisting of eight large and eight small subunits arranged in the way that seems to be typical for this enzyme in higher plants.

Ostwald ripening of cobalt precipitates in silica aerogels? An ultra-small-angle X-ray scattering study

2005 ◽  
Vol 38 (1) ◽  
pp. 132-138 ◽  
Author(s):  
Artur Braun ◽  
Jan Ilavsky ◽  
Brian C. Dunn ◽  
Pete R. Jemian ◽  
Frank E. Huggins ◽  
...  
Keyword(s):  
Size Distribution ◽  
Small Angle ◽  
Ostwald Ripening ◽  
Supercritical Drying ◽  
Silica Aerogels ◽  
Radial Symmetry ◽  
Radius Of Gyration ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Monolithic silica aerogels with radial symmetry were synthesized by supercritical drying, doped to 2% and 10% with cobalt, and reduced with hydrogen. All samples were investigated with ultra-small-angle X-ray scattering. The non-doped aerogels have three populations of scatterers with radii of gyration of about 10, 40 and 60–70 Å. The doped aerogels show an additional structure with a radius of gyration ranging from 1050 to 3000 Å. This structure causes intensity oscillations, thus revealing a relatively narrow size distribution. Scattering curves of the 10%-doped aerogels fitted well to a Lifshitz–Slyozov–Wagner particle size distribution, thus revealing that Ostwald ripening might have occurred during aerogel preparation. The same range also shows differences depending on whether the samples were reduced, or in their as-prepared condition. Scattering curves obtained from the cylinder-axis region were different from the scattering curves obtained from the sample boundary, indicating a process-dependent skin effect.

scholarly journals Guinier peak analysis for visual and automated inspection of small-angle X-ray scattering data

2016 ◽  
Vol 49 (5) ◽  
pp. 1412-1419 ◽  
Author(s):  
Christopher D. Putnam
Keyword(s):  
Small Angle ◽  
Peak Position ◽  
Scattering Data ◽  
Radius Of Gyration ◽  
Automated Inspection ◽  
Elongation Ratio ◽  
Saxs Data ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

The Guinier region in small-angle X-ray scattering (SAXS) defines the radius of gyration,Rg, and the forward scattering intensity,I(0). In Guinier peak analysis (GPA), the plot ofqI(q)versus q2transforms the Guinier region into a characteristic peak for visual and automated inspection of data. Deviations of the peak position from the theoretical position in dimensionless GPA plots can suggest parameter errors, problematic low-resolution data, some kinds of intermolecular interactions or elongated scatters. To facilitate automated analysis by GPA, the elongation ratio (ER), which is the ratio of the areas in the pair-distribution functionP(r) after and before theP(r) maximum, was characterized; symmetric samples have ER values around 1, and samples with ER values greater than 5 tend to be outliers in GPA analysis. Use of GPA+ER can be a helpful addition to SAXS data analysis pipelines.

Determination of small alterations in the radius of gyration by small-angle X-ray scattering

1971 ◽  
Vol 4 (4) ◽  
pp. 317-318 ◽  
Author(s):  
I. Simon
Keyword(s):  
Small Angle ◽  
Direct Determination ◽  
Differential Method ◽  
Scattering Data ◽  
Radius Of Gyration ◽  
X Ray ◽  
X Ray Scattering ◽  
Colloid Particles ◽  
Ray Scattering

A differential method is presented for the evaluation of small-angle X-ray scattering data. The direct determination of slight changes in the radius of gyration of colloid particles is rendered possible by the method proposed.

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