Main Chain Conformation and Anomalous Elution Behavior of Cylindrical Brushes As Revealed by GPC/MALLS, Light Scattering, and SFM‡

1999 ◽  
Vol 32 (8) ◽  
pp. 2629-2637 ◽  
Author(s):  
Markus Gerle ◽  
Karl Fischer ◽  
Sebastian Roos ◽  
Axel H. E. Müller ◽  
Manfred Schmidt ◽  
...  
Keyword(s):  
Light Scattering ◽  
Main Chain ◽  
Chain Conformation ◽  
Elution Behavior

Chain Conformation of Poly(d-lactide) in Tetrahydrofuran by Static Light Scattering, Small-Angle X-ray Scattering, and Intrinsic Viscosity

2020 ◽  
Vol 53 (5) ◽  
pp. 1604-1612 ◽  
Author(s):  
Yoshinori Suzuki ◽  
Takahiro Watanabe ◽  
Hiroki Kosugi ◽  
Kayo Ueda ◽  
Moriya Kikuchi ◽  
...  
Keyword(s):  
Light Scattering ◽  
Intrinsic Viscosity ◽  
Small Angle ◽  
Chain Conformation ◽  
Static Light Scattering ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

OH Radical-Induced Main-Chain Scission of Poly(Ribonucleic Acids) under Anoxic Conditions

1983 ◽  
Vol 38 (1-2) ◽  
pp. 100-106 ◽  
Author(s):  
Komei Washino ◽  
Otmar Denk ◽  
Wolfram Schnabel
Keyword(s):  
Light Scattering ◽  
Main Chain ◽  
Degradation Mechanism ◽  
Chain Scission ◽  
Oh Radicals ◽  
Ribonucleic Acids ◽  
Chemical Mechanisms ◽  
Dilute Aqueous Solution ◽  
Ribose Moiety ◽  
Rayleigh Light

Poly(ribonucleic acids), poly A, poly C and poly U, were irradiated in O2-free dilute aqueous solution at pH 7 to 8 with single pulses (50 to 200 ns) of 16MeV electrons. With the aid of Rayleigh light scattering measurements main-chain scission, induced by OH radicals, was observed with the three polynucleotides. From the time dependence of the decrease of the light scattering intensity (LSI), the existence of two modes of decrease was inferred, indicating at least two different chemical mechanisms were operative in main-chain degradation. Evidence for the assignment of the slow mode of LSI decrease to the lifetime of a free radical was obtained from quenching experiments with cysteamine. It is noteworthy, that the extent and the lifetime of LSI decrease are not the same for the three polynucleotides. The differences indicate the influence of the chemical nature of the bases on main-chain scission. Consequently, it is concluded that OH attack at carbons in 1′ and/or 2′ position of the ribose moiety contributes essentially to the degradation mechanism.

Study of the effect of aggregation on the structure of syndiotactic poly(methyl methacrylate) by infrared spectra of its deuterated analogues

1984 ◽  
Vol 49 (10) ◽  
pp. 2259-2268 ◽  
Author(s):  
Jiří Dybal ◽  
Bohdan Schneider ◽  
Marian Mihailov
Keyword(s):  
Methyl Methacrylate ◽  
Infrared Spectra ◽  
Main Chain ◽  
Chain Conformation ◽  
Conformational Structure ◽  
Poly Methyl Methacrylate ◽  
Carbon Backbone ◽  
Temperature Trends ◽  
Extended Chain ◽  
Vibrational Bands

The temperature trends of the infrared spectra of the films of some specifically deuterated analogues of syndiotactic poly(methyl methacrylate) were measured and vibrational bands sensitive to the conformational structure of the carbon backbone and to the orientation of ester groups with respect to the main chain were determined. Analysis of the spectra has confirmed that aggregated syndiotactic poly(methyl methacrylate) contains a higher population of diads in the extended chain conformation in long syndiotactic sequences as compared to the nonaggregated polymer, and has shown that in the aggregate, ordering of ester groups also takes place.

scholarly journals Ultrasonic-Assisted Extraction, Structural Characterization, Chain Conformation, and Biological Activities of a Pectic-Polysaccharide from Okra (Abelmoschus esculentus)

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1155 ◽  
Author(s):  
Xi-Rui Nie ◽  
Yuan Fu ◽  
Ding-Tao Wu ◽  
Ting-Ting Huang ◽  
Qin Jiang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Chain Conformation ◽  
Size Exclusion ◽  
Pectic Polysaccharide ◽  
Assisted Extraction ◽  
Ultrasonic Assisted ◽  
Pharmaceutical Industries ◽  
Ultrasonic Assisted Extraction

The purpose of this study was to better understand the chemical characteristics and chain conformation of okra polysaccharides extracted by ultrasonic-assisted extraction. A pectic-polysaccharide, named OPP-D, was obtained, which was mainly composed of rhamnose, galacturonic acid, and galactose with a molar ratio of 1.01:1.00:2.31. Combined with NMR analysis, -4)-α-d-GalAp-(1,2,4)-α-l-Rhap-(1- were identified as the backbone with galactan side chains substituted partly at O-4 of Rhap. Molecular weight and radius of gyration of OPP-D were determined as 2.19 × 105 Da and 27.0 nm, respectively. OPP-D was determined as an air-core sphere with branching chains in 0.9% NaCl solution by high-performance size-exclusion chromatography coupled with multi-angle laser light scattering and dynamic light scattering for the first time. Moreover, OPP-D exhibited typical shear-thinning behavior. In addition, OPP-D exhibited remarkable in vitro antioxidant activities and prebiotic activities, while the relatively high molecular weight, high degree of esterification, high content of uronic acids, and highly branched globular conformation of OPP-D might contribute to its in vitro anti-diabetic activities and binding capacities. Results can contribute to a better understanding of the structure–bioactivity relationship of OPPs, and OPP-D has great potential applications in the functional food and pharmaceutical industries.

scholarly journals Mechanisms of Deamidation of Asparagine Residues and Effects of Main-Chain Conformation on Activation Energy

2020 ◽  
Vol 21 (19) ◽  
pp. 7035
Author(s):  
Koichi Kato ◽  
Tomoki Nakayoshi ◽  
Eiji Kurimoto ◽  
Akifumi Oda
Keyword(s):  
Activation Energy ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Density Functional ◽  
Main Chain ◽  
Density Functional Method ◽  
Md Simulations ◽  
Chain Conformation ◽  
Dihydrogen Phosphate ◽  
Chain Conformations

Deamidation of asparagine (Asn) residues is a nonenzymatic post-translational modification of proteins. Asn deamidation is associated with pathogenesis of age-related diseases and hypofunction of monoclonal antibodies. Deamidation rate is known to be affected by the residue following Asn on the carboxyl side and by secondary structure. Information about main-chain conformation of Asn residues is necessary to accurately predict deamidation rate. In this study, the effect of main-chain conformation of Asn residues on deamidation rate was computationally investigated using molecular dynamics (MD) simulations and quantum chemical calculations. The results of MD simulations for γS-crystallin suggested that frequently deamidated Asn residues have common main-chain conformations on the N-terminal side. Based on the simulated structure, initial structures for the quantum chemical calculations were constructed and optimized geometries were obtained using the B3LYP density functional method. Structures that were frequently deamidated had a lower activation energy barrier than that of the little deamidated structure. We also showed that dihydrogen phosphate and bicarbonate ions are important catalysts for deamidation of Asn residues.

Study of the chain conformation of thermotropic nematic main chain polyesters

1994 ◽  
Vol 4 (10) ◽  
pp. 1843-1863 ◽  
Author(s):  
M. H. Li ◽  
A. Brûlet ◽  
J. P. Cotton ◽  
P. Davidson ◽  
C. Strazielle ◽  
...  
Keyword(s):  
Main Chain ◽  
Chain Conformation

Direct observation of the main-chain conformation of a combined liquid-crystal polymer

1995 ◽  
Vol 18 (1) ◽  
pp. 123-127 ◽  
Author(s):  
L. Noirez ◽  
H. Poths ◽  
R. Zentel ◽  
C. Strazielle
Keyword(s):  
Liquid Crystal ◽  
Direct Observation ◽  
Main Chain ◽  
Liquid Crystal Polymer ◽  
Chain Conformation ◽  
Crystal Polymer
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