scholarly journals Structural Investigation of Oat Protein Isolate in Aqueous Medium by using Synchrotron Small-angle X-ray Scattering

2020 ◽  
Author(s):  
Ji Li ◽  
Qingrong Huang
Keyword(s):  
Aqueous Medium ◽  
Small Angle ◽  
Second Virial Coefficient ◽  
Pair Potential ◽  
Protein Isolate ◽  
Small Scale ◽  
X Ray ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Ray Scattering

AbstractOat protein isolate (OPI) is among the plant proteins with valuable functionalities (e.g. emulsification) during daily supplement intake. Understanding their structures helps to manipulate oat proteins at small scale, which enables the appropriate deployment of their functions. Based upon such understanding, the molecular structure of oat protein isolate (OPI) in aqueous medium was investigated by synchrotron small-angle X-ray scattering (SAXS), and this study allows a structural reconstitution of OPI in aqueous medium. Besides, this SAXS study is complimentary to the previous study (Liu et al. J. Agric. Food Chem. 2009, 57, 4552–4558)1. From form factor fitting, we confirmed that OPI aqueous solutions at low concentrations (0.3~2 mg/mL) obtained a disk conformation (41.4×41.4×10.2 Å3). Once protein concentration increased to 5 mg/mL and 10 mg/mL, the individual disk proteins formed large-dimensional rodlike aggregates, which was evidenced by the analyses of effective structure factor and pair distribution function (PDF). Based on the PDF results, the ab initio models of OPI particles at low concentrations (0.3 mg/mL to 2.0 mg/mL) were restored by using GASBOR algorithm. Finally, we found that weak attraction between OPI particles occurred, which was verified by second virial coefficient and pair potential.

Small-scale screening method for low-viscosity antibody solutions using small-angle X-ray scattering

2017 ◽  
Vol 112 ◽  
pp. 132-137 ◽  
Author(s):  
Masakazu Fukuda ◽  
Atsushi Watanabe ◽  
Akira Hayasaka ◽  
Masaru Muraoka ◽  
Yuji Hori ◽  
...  
Keyword(s):  
Small Angle ◽  
Screening Method ◽  
Small Scale ◽  
X Ray ◽  
Low Viscosity ◽  
X Ray Scattering ◽  
Ray Scattering

A Small-Angle X-ray Scattering Study of the Lyotropic Nematic Phase of Vanadium Pentoxide Gels

1997 ◽  
Vol 30 (5) ◽  
pp. 727-732 ◽  
Author(s):  
P. Davidson ◽  
C. Bourgaux ◽  
P. Sergot ◽  
J. Livage
Keyword(s):  
Vanadium Pentoxide ◽  
Small Angle ◽  
Nematic Phase ◽  
Average Distance ◽  
Building Blocks ◽  
X Ray ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Nematic Phases ◽  
Ray Scattering

Aqueous suspensions of vanadium pentoxide (V2O5) ribbons, also called Zocher phases, are known to display a lyotropic nematic phase. In this paper, it is shown how the small-angle X-ray scattering (SAXS) technique can provide useful information on the building blocks and their organization in this phase. SAXS experiments were performed either on unoriented samples or on samples aligned by a magnetic field or by shear flow. The scattering is comparable to that of the other classic lyotropic nematic phases displayed by stiff organic rod-like particles such as the tobacco mosaic virus. Scattering studies show that the building blocks have a ribbon shape, that their thickness is 9 (1) Å and indirectly that their width is several 100 Å. Their length is known to be around a few thousand Å and therefore could not be measured by SAXS. By following the average distance between the ribbons as a function of concentration, it is shown that the swelling of the phase is one-dimensional at large concentrations and two-dimensional at low concentrations. Finally, estimates of the nematic order parameter of a single domain sample and of samples sheared in a Couette cell have been obtained.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

A Revised O2 Reduction Model in Li-O2 Batteries as Revealed by in Situ Small Angle X-Ray Scattering

2019 ◽  
Author(s):  
Christian Prehal ◽  
Aleksej Samojlov ◽  
Manfred Nachtnebel ◽  
Manfred Kriechbaum ◽  
Heinz Amenitsch ◽  
...  
Keyword(s):  
Small Angle ◽  
Wide Angle ◽  
Reduction Mechanism ◽  
Reduction Model ◽  
X Ray ◽  
X Ray Scattering ◽  
O2 Reduction ◽  
Ray Scattering

<b>Here we use in situ small and wide angle X-ray scattering to elucidate unexpected mechanistic insights of the O2 reduction mechanism in Li-O2 batteries.<br></b>

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

Small angle X-ray scattering study of porosity variation in a styrene-divinylbenzene copolymer

1981 ◽  
Vol 46 (7) ◽  
pp. 1675-1681 ◽  
Author(s):  
Josef Baldrian ◽  
Božena N. Kolarz ◽  
Henrik Galina
Keyword(s):  
Small Angle ◽  
Structural Parameters ◽  
Two Phase ◽  
X Ray ◽  
Porosity Variation ◽  
Swelling Agent ◽  
X Ray Scattering ◽  
Styrene Divinylbenzene ◽  
Ray Scattering

Porosity variations induced by swelling agent exchange were studied in a styrene-divinylbenzene copolymer. Standard methods were used in the characterization of copolymer porosity in the dry state and the results were compared with related structural parameters derived from small angle X-ray scattering (SAXS) measurements as developed for the characterization of two-phase systems. The SAXS method was also used for porosity determination in swollen samples. The differences in the porosity of dry samples were found to be an effect of the drying process, while in the swollen state the sample swells and deswells isotropically.

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