X-Ray and Neutron Instrumentation

Feĭgin, L. A.; Svergun, D. I.; Taylor, George W.

doi:10.1007/978-1-4757-6624-0_8

Cited by 72 publications

(95 citation statements)

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“…SAXS Data Analysis-All data analysis was carried out using the SAXS program package Atsas developed at the European Molecular Biology Laboratory by Svergun and co-worker (38). The net protein scattering data, I(q), were generated by subtraction from scattering of the same buffer using PRIMUS (38) or software developed at beamline X9 at the National Synchrotron Light Source (46).…”

Section: Methodsmentioning

confidence: 99%

Insights into Mechanism of Glucokinase Activation

Liu

Ammirati

Song

et al. 2012

Journal of Biological Chemistry

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Background: Human glucokinase (GK) is a principal regulator of glucose homeostasis. Results: The structure of the catalytic complex of GK has been determined, and multiple conformations have been directly observed in solution. Conclusion: In solution, glucose dose-dependently converts GK from the apo conformation to an active open conformation. Significance: Understanding the conformational changes of GK during the reaction is crucial for designing better glucokinase activators with safer profiles.

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Section: Methodsmentioning

confidence: 99%

Insights into Mechanism of Glucokinase Activation

Liu

Ammirati

Song

et al. 2012

Journal of Biological Chemistry

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“…The interpretation of small-angle X-ray and neutron scattering data plays an essential role in the determination of size, shape and internal structure of colloidal particles in the size range from a few nanometers up to about a hundred nanometers (Guinier & Fournet, 1955;Glatter & Kratky, 1982;Feigin & Svergun, 1987;Brumberger, 1995). As long as the solutions are dilute, there exists a direct relation between the particle [represented by its pair-distance-distribution function p(r)] and its scattering data by means of a Fourier transformation.…”

Section: Introductionmentioning

confidence: 99%

Small-angle scattering of interacting particles. II. Generalized indirect Fourier transformation under consideration of the effective structure factor for polydisperse systems

1999

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The indirect Fourier transformation (IFT) is the method of choice for the model-free evaluation of small-angle scattering data. Unfortunately, this technique is only useful for dilute solutions because, for higher concentrations, particle interactions can no longer be neglected. Thus an advanced technique was developed as a generalized version, the so-called generalized indirect Fourier transformation (GIFT). It is based on the simultaneous determination of the form factor, representing the intraparticle contributions, and the structure factor, describing the interparticle contributions. The former can be determined absolutely free from model assumptions, whereas the latter has to be calculated according to an adequate model. In this paper, various models for the structure factor are compared, e.g. the effective structure factor for polydisperse hard spheres, the averaged structure factor, the local monodisperse approximation and the decoupling approximation. Furthermore, the structure factor for polydisperse rodlike particles is presented. As the model-free evaluation of small-angle scattering data is an essential point of the GIFT technique, the use of a structure factor without any in¯uence of the form amplitude is advisable, at least during the ®rst evaluation procedure. Therefore, a series of simulations are performed to check the possibility of the representation of various structure factors (such as the effective structure factor for hard spheres or the structure factor for rod-like particles) by the less exact but much simpler averaged structure factor. In all the observed cases, it was possible to recover the exact form factor with a free determined parameter set for the structure factor. The resulting parameters of the averaged structure factor have to be understood as apparent model parameters and therefore have only limited physical relevance. Thus the GIFT represents a technique for the model independent evaluation of scattering data with a minimum of a priori information.

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“…Small-angle scattering of X-rays (SAXS) and neutrons (SANS) are widely used and powerful techniques for determining size, shape and internal structure of particles in the size range from a few nm up to about 100 nm (Guinier & Fournet, 1955;Glatter & Kratky, 1982;Feigin & Svergun, 1987;Lindner & Zemb, 1991;Brumberger, 1995). They are mainly applied to systems of randomly oriented and statistically distributed structures of colloidal dimensions, such as micellar aggregates, proteins and polymers in solution or precipitates in amorphous materials.…”

Section: Introductionmentioning

confidence: 99%

Direct Structure Analysis of Small-Angle Scattering Data from Polydisperse Colloidal Particles

Mittelbach¹,

Glatter²

1998

J Appl Cryst

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The internal structure of colloidal particles of spherical, rod-like or lamellar symmetry can be determined from small-angle scattering data by means of the well established 'indirect Fourier transformation' technique followed by the numerical deconvolution of the pair distance distribution function. The method works without any preliminary knowledge of the particles under investigation except a rough estimate of their maximal size. However, its use has hitherto been restricted to monodisperse or very weakly polydisperse systems. In this paper a new method is presented that is capable of determining the radial scattering length density distribution of particles in strongly polydisperse samples and provides a parameter that quantifies the degree of polydispersity present in the system. The only additional information necessary is the function type which describes the size distribution of the particles under investigation in the best way possible. However, the method is limited to polydisperse systems which may be characterized by only one linear size parameter. In addition, it is now possible to represent the density profile by smooth spline functions, i.e. the technique is no longer restricted to step functions as basis functions. The mathematical procedure is outlined in detail and numerical results of simulations as well as of experimental data from small-angle neutron scattering and small-angle X-ray scattering measurements of surfactant aggregates in water and water/oil systems are given.

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X-Ray and Neutron Instrumentation

Cited by 72 publications

References 0 publications

Insights into Mechanism of Glucokinase Activation

Insights into Mechanism of Glucokinase Activation

Small-angle scattering of interacting particles. II. Generalized indirect Fourier transformation under consideration of the effective structure factor for polydisperse systems

Direct Structure Analysis of Small-Angle Scattering Data from Polydisperse Colloidal Particles

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