Memory effect in tetra-n-butyl ammonium bromide semiclathrate hydrate reformation: the existence of solution structures after hydrate decomposition

CrystEngComm ◽  
2018 ◽  
Vol 20 (24) ◽  
pp. 3328-3334 ◽  
Author(s):  
Hironobu Machida ◽  
Takeshi Sugahara ◽  
Izumi Hirasawa
Keyword(s):  
Memory Effect ◽  
Solution Structure ◽  
Existence Of Solution ◽  
Ammonium Bromide ◽  
Solution Structures ◽  
Hydrate Decomposition ◽  
Residual Solution ◽  
Semiclathrate Hydrate

The memory effect in TBAB semiclathrate hydrate reformation results from the residual solution structure composed of clusters and cluster aggregates.

scholarly journals Solution structures of long-acting insulin analogues and their complexes with albumin

2019 ◽  
Vol 75 (3) ◽  
pp. 272-282 ◽  
Author(s):  
Line A. Ryberg ◽  
Pernille Sønderby ◽  
Fabian Barrientos ◽  
Jens T. Bukrinski ◽  
Günther H. J. Peters ◽  
...  
Keyword(s):  
Solution Structure ◽  
Insulin Analogues ◽  
Size Exclusion ◽  
Life Extension ◽  
Once Daily ◽  
Solution Structures ◽  
X Ray Scattering ◽  
Exclusion Chromatography ◽  
Self Association ◽  
Long Acting

The lipidation of peptide drugs is one strategy to obtain extended half-lives, enabling once-daily or even less frequent injections for patients. The half-life extension results from a combination of self-association and association with human serum albumin (albumin). The self-association and association with albumin of two insulin analogues, insulin detemir and insulin degludec, were investigated by small-angle X-ray scattering (SAXS) and dynamic light scattering (DLS) in phenolic buffers. Detemir shows concentration-dependent self-association, with an equilibrium between hexamer, dihexamer, trihexamer and larger species, while degludec appears as a dihexamer independent of concentration. The solution structure of the detemir trihexamer has a bent shape. The stoichiometry of the association with albumin was studied using DLS. For albumin–detemir the molar stoichiometry was determined to be 1:6 (albumin:detemir ratio) and for albumin–degludec it was between 1:6 and 1:12 (albumin:degludec ratio). Batch SAXS measurements of a 1:6 albumin:detemir concentration series revealed a concentration dependence of complex formation. The data allowed the modelling of a complex between albumin and a detemir hexamer and a complex consisting of two albumins binding to opposite ends of a detemir dihexamer. Measurements of size-exclusion chromatography coupled to SAXS revealed a complex between a degludec dihexamer and albumin. Based on the results, equilibria for the albumin–detemir and albumin–degludec mixtures are proposed.

Methane Separation from Coal Mine Methane Gas by Tetra-n-butyl Ammonium Bromide Semiclathrate Hydrate Formation

2012 ◽  
Vol 26 (4) ◽  
pp. 2098-2106 ◽  
Author(s):  
Dongliang Zhong ◽  
Peter Englezos
Keyword(s):  
Coal Mine ◽  
Hydrate Formation ◽  
Ammonium Bromide ◽  
Coal Mine Methane ◽  
Methane Gas ◽  
Semiclathrate Hydrate

Growth Kinetics of Tetra-N-Butyl Ammonium Bromide Semiclathrate Hydrate through Concentration Determination and Microscopic Observation

2011 ◽  
Vol 383-390 ◽  
pp. 3121-3127 ◽  
Author(s):  
Shuan Shi Fan ◽  
Juan Du ◽  
Yan Hong Wang ◽  
Xue Mei Lang
Keyword(s):  
Growth Kinetics ◽  
Growth Velocity ◽  
Microscopic Observation ◽  
Observation System ◽  
Ammonium Bromide ◽  
Weighting Method ◽  
Concentration Determination ◽  
Kinetics Of ◽  
Varied Concentration ◽  
Semiclathrate Hydrate

Growth kinetics of TBAB semiclathrate forming from 32wt% aqueous solution at 10±1°C and atmospheric pressure was studied through macro concentration determination and microscopic observation. The varied concentration from which the hydrate formed was measured in the range of 32wt% ~ 24wt% by means of weighting method, based on which three-stage hydration process was proposed. The morphology of TBAB hydrate crystals and growing velocity were then investigated based on a microscopic observation system. Coexistent morphology of TBAB semiclathrate hydrate crystals was obtained for the first time, with the single crystals in tetragonous, hexagonous, and octagonous columnar shapes. In the kinetics analysis, the growth velocity of TBAB semiclathrate hydrate crystals was calculated. Equation of the crystal growth for tetragonous and octagonous columnar crystals was worked out in combination of the varied concentration and the growth velocity. And to our best knowledge, no kinetics formula has been reported on the two shapes of TBAB semiclathrate hydrate crystals.

Solution Structures of Pyrophthalones, II [1]. Structure and Conformation of Iminopyrophthalone — a High Resolution 1H, 13C, 15N and Solid State 13C-CP/MAS-NMR Study

1987 ◽  
Vol 42 (11) ◽  
pp. 1419-1423 ◽  
Author(s):  
Erhard T. K. Haupt ◽  
Heindirk tom Dieck ◽  
Panayot R. Bontchev
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Nmr Spectra ◽  
Solution Structure ◽  
Complete Analysis ◽  
State Structure ◽  
Solution Structures ◽  
Nmr Study ◽  
Cp Mas Nmr ◽  
13C Cp Mas Nmr

The complete analysis of the 1H, 13C, 15N NMR spectra of iminopyrophthalone demonstrates that the solution structure of the molecule must be described as a protonated iminocompound. 13C-CP/MAS spectroscopy proves that the solid state structure of α-PPH and IPH are equivalent to the solution structure.

Crystal and solution structures of the B-DNA dodecamer d(CGCAAATTTGCG) probed by Raman spectroscopy: heterogeneity in the crystal structure does not persist in the solution structure

Biochemistry ◽  
1988 ◽  
Vol 27 (3) ◽  
pp. 931-938 ◽  
Author(s):  
J. M. Benevides ◽  
A. H. J. Wang ◽  
G. A. Van der Marel ◽  
J. H. Van Boom ◽  
G. J. Thomas
Keyword(s):  
Crystal Structure ◽  
Raman Spectroscopy ◽  
Solution Structure ◽  
Solution Structures ◽  
Dna Dodecamer

scholarly journals Small-angle neutron scattering studies on the AMPA receptor GluA2 in the resting, AMPA-bound and GYKI-53655-bound states

IUCrJ ◽  
2018 ◽  
Vol 5 (6) ◽  
pp. 780-793 ◽  
Author(s):  
Andreas Haahr Larsen ◽  
Jerzy Dorosz ◽  
Thor Seneca Thorsen ◽  
Nicolai Tidemand Johansen ◽  
Tamim Darwish ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Ampa Receptor ◽  
Small Angle ◽  
Resting State ◽  
Small Angle Neutron Scattering ◽  
Solution Structure ◽  
Compact Form ◽  
Allosteric Modulator ◽  
Solution Structures ◽  
Negative Allosteric Modulator

The AMPA receptor GluA2 belongs to the family of ionotropic glutamate receptors, which are responsible for most of the fast excitatory neuronal signalling in the central nervous system. These receptors are important for memory and learning, but have also been associated with brain diseases such as Alzheimer's disease and epilepsy. Today, one drug is on the market for the treatment of epilepsy targeting AMPA receptors, i.e. a negative allosteric modulator of these receptors. Recently, crystal structures and cryo-electron microscopy (cryo-EM) structures of full-length GluA2 in the resting (apo), activated and desensitized states have been reported. Here, solution structures of full-length GluA2 are reported using small-angle neutron scattering (SANS) with a novel, fully matched-out detergent. The GluA2 solution structure was investigated in the resting state as well as in the presence of AMPA and of the negative allosteric modulator GYKI-53655. In solution and at neutral pH, the SANS data clearly indicate that GluA2 is in a compact form in the resting state. The solution structure resembles the crystal structure of GluA2 in the resting state, with an estimated maximum distance (D max) of 179 ± 11 Å and a radius of gyration (R g) of 61.9 ± 0.4 Å. An ab initio model of GluA2 in solution generated using DAMMIF clearly showed the individual domains, i.e. the extracellular N-terminal domains and ligand-binding domains as well as the transmembrane domain. Solution structures revealed that GluA2 remained in a compact form in the presence of AMPA or GYKI-53655. At acidic pH only, GluA2 in the presence of AMPA adopted a more open conformation of the extracellular part (estimated D max of 189 ± 5 Å and R g of 65.2 ± 0.5 Å), resembling the most open, desensitized class 3 cryo-EM structure of GluA2 in the presence of quisqualate. In conclusion, this methodological study may serve as an example for future SANS studies on membrane proteins.

Crystal and solution structures of a novel antimicrobial peptide from Chrysomya megacephala

2021 ◽  
Vol 77 (7) ◽  
Author(s):  
Chengliang Xiao ◽  
Zaiyu Xiao ◽  
Cuifang Hu ◽  
Jie Lu ◽  
Liwei Cui ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ab Initio ◽  
Solution Structure ◽  
Mitochondrial Atpase ◽  
Microbial Infection ◽  
Atpase Inhibitor ◽  
Apparent Contradiction ◽  
Chrysomya Megacephala ◽  
Solution Structures ◽  
Wide Range

Antimicrobial peptides (AMPs) are small amphipathic peptides that exhibit bactericidal activity against a wide range of pathogenic microorganisms and are considered to be potential substitutes for antibiotics effective against microbial infection. PSK, an 84-amino-acid AMP recently isolated from Chrysomya megacephala larvae, probably belongs to the mitochondrial ATPase inhibitor family according to its sequence. No member of this family from an insect has been structurally characterized to date. In this study, the crystal structure of full-length PSK determined by molecular replacement using an ab initio modeled ensemble as a search model and a solution structure obtained from small-angle X-ray scattering (SAXS) measurements are reported. The crystal structure reveals a distinct fold compared with those of homologous peptides, in that PSK comprises two antiparallel α-helices rather than a single long helix, which is in good agreement with the SAXS-based ab initio model. However, the peptide exists as a monomer in solution, even though a stable dimer was observed in the crystal structure. This apparent contradiction may reflect different oligomerization states that may be implicated in its bioactivity. The data presented here have established a solid basis for further mechanistic studies of this novel insect AMP.

Application of the Solution Structure Method in Numerically Solving Poisson’s Equation on the Basis of Atomic Functions

2018 ◽  
Vol 15 (05) ◽  
pp. 1850033 ◽  
Author(s):  
Vedrana Kozulić ◽  
Blaž Gotovac
Keyword(s):  
Differential Equation ◽  
Boundary Value Problem ◽  
Solution Structure ◽  
Analytical Form ◽  
Basis Functions ◽  
Torsion Problem ◽  
Solution Structures ◽  
The Third ◽  
Collocation Technique ◽  
Unknown Component

This paper summarizes the main principles of the solution structure method and presents it in combination with atomic basis functions and a collocation technique. The solution of a boundary value problem is expressed in the form of formulae called solution structures, which depend on three components: the first component describes the geometry of the domain exactly in the analytical form, the second describes all boundary conditions exactly, and the third component, that contains information about the differential equation, is the unknown component represented by a linear combination of atomic basis functions. The proposed method is applied to solve the torsion problem.

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