scholarly journals Dynamics of Quaternary Structure Transitions in R-State Carbonmonoxyhemoglobin Unveiled in Time-Resolved X-ray Scattering Patterns Following a Temperature Jump

2018 ◽  
Vol 122 (49) ◽  
pp. 11488-11496 ◽  
Author(s):  
Hyun Sun Cho ◽  
Friedrich Schotte ◽  
Valentyn Stadnytskyi ◽  
Anthony DiChiara ◽  
Robert Henning ◽  
...  
Keyword(s):  
Temperature Jump ◽  
Quaternary Structure ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Singular value decomposition analysis of time-resolved small-angle X-ray scattering during morphological transition in a block copolymer

2003 ◽  
Vol 36 (4) ◽  
pp. 982-985 ◽  
Author(s):  
Shigeru Okamoto ◽  
Shinichi Sakurai
Keyword(s):  
Block Copolymer ◽  
Singular Value Decomposition ◽  
Temperature Jump ◽  
Singular Value ◽  
Morphological Transition ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Value Decomposition ◽  
Ray Scattering

Time-resolved small-angle X-ray scattering (TR-SAXS) studies of the structural changes in a block copolymer after a temperature jump are reported. The sample used was a polystyrene-block-poly(ethylene-alt-butylene)-block-polystyrene (SEBS) triblock copolymer, which has a number-average molecular weight of 54000 g mol−1and a volume fraction of polystyrene of 0.227. The film specimen was prepared by the solution-cast method using a selective solvent. The as-cast specimen with lamellar microdomains underwent the temperature jump from 363 to 403 K and the morphological transition from lamellae to cylinders was observed as a function of time by the TR-SAXS technique. The singular value decomposition (SVD) analysis was performed on the scattering profiles. This analysis strongly suggested the existence of a third basis component of the X-ray scattering profiles, thus supporting that there is an intermediate state during the transition from lamellae to cylinders.

scholarly journals Insulin hexamer dissociation dynamics revealed by photoinduced T-jumps and time-resolved X-ray solution scattering

2018 ◽  
Vol 17 (7) ◽  
pp. 874-882 ◽  
Author(s):  
Dolev Rimmerman ◽  
Denis Leshchev ◽  
Darren J. Hsu ◽  
Jiyun Hong ◽  
Baxter Abraham ◽  
...  
Keyword(s):  
Structural Dynamics ◽  
Temperature Jump ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Dissociation Dynamics ◽  
Ray Scattering

The structural dynamics of insulin hexamer dissociation were studied by the photoinduced temperature jump technique and monitored by time-resolved X-ray scattering.

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.

Time-Resolved Cryo-Electron Microscopy of Oscillating Microtubules

1990 ◽  
Vol 48 (1) ◽  
pp. 502-503
Author(s):  
Eva-Maria Mandelkow ◽  
Ron Milligan
Keyword(s):  
Electron Microscopy ◽  
Dynamic Instability ◽  
Entire Solution ◽  
Reaction Scheme ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
A Chain ◽  
Ray Scattering

Microtubules form part of the cytoskeleton of eukaryotic cells. They are hollow libers of about 25 nm diameter made up of 13 protofilaments, each of which consists of a chain of heterodimers of α-and β-tubulin. Microtubules can be assembled in vitro at 37°C in the presence of GTP which is hydrolyzed during the reaction, and they are disassembled at 4°C. In contrast to most other polymers microtubules show the behavior of “dynamic instability”, i.e. they can switch between phases of growth and phases of shrinkage, even at an overall steady state [1]. In certain conditions an entire solution can be synchronized, leading to autonomous oscillations in the degree of assembly which can be observed by X-ray scattering (Fig. 1), light scattering, or electron microscopy [2-5]. In addition such solutions are capable of generating spontaneous spatial patterns [6].In an earlier study we have analyzed the structure of microtubules and their cold-induced disassembly by cryo-EM [7]. One result was that disassembly takes place by loss of protofilament fragments (tubulin oligomers) which fray apart at the microtubule ends. We also looked at microtubule oscillations by time-resolved X-ray scattering and proposed a reaction scheme [4] which involves a cyclic interconversion of tubulin, microtubules, and oligomers (Fig. 2). The present study was undertaken to answer two questions: (a) What is the nature of the oscillations as seen by time-resolved cryo-EM? (b) Do microtubules disassemble by fraying protofilament fragments during oscillations at 37°C?

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.

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