scholarly journals Influence of Calcium Binding on Conformations and Motions of Anionic Polyamino Acids. Effect of Side Chain Length

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1279
Author(s):  
Dmitry Tolmachev ◽  
Natalia Lukasheva ◽  
George Mamistvalov ◽  
Mikko Karttunen
Keyword(s):  
Amino Acids ◽  
Chain Length ◽  
Calcium Binding ◽  
Md Simulations ◽  
Side Chain ◽  
Replica Exchange ◽  
Side Chain Length ◽  
Hamiltonian Replica Exchange ◽  
Cacl2 Concentration ◽  
Chain Lengths

Investigation of the effect of CaCl2 salt on conformations of two anionic poly(amino acids) with different side chain lengths, poly-(α-l glutamic acid) (PGA) and poly-(α-l aspartic acid) (PASA), was performed by atomistic molecular dynamics (MD) simulations. The simulations were performed using both unbiased MD and the Hamiltonian replica exchange (HRE) method. The results show that at low CaCl2 concentration adsorption of Ca2+ ions lead to a significant chain size reduction for both PGA and PASA. With the increase in concentration, the chains sizes partially recover due to electrostatic repulsion between the adsorbed Ca2+ ions. Here, the side chain length becomes important. Due to the longer side chain and its ability to distance the charged groups with adsorbed ions from both each other and the backbone, PGA remains longer in the collapsed state as the CaCl2 concentration is increased. The analysis of the distribution of the mineral ions suggests that both poly(amino acids) should induce the formation of mineral with the same structure of the crystal cell.

scholarly journals Effect of Side Chain Length on Polycarboxylate Superplasticizer in Aqueous Solution: A Computational Study

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 346 ◽  
Author(s):  
Po-Hsiang Chuang ◽  
Yu-Hui Tseng ◽  
Yunhui Fang ◽  
Miaomiao Gui ◽  
Xiuxing Ma ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Chain Length ◽  
Computational Study ◽  
Side Chain ◽  
Water Molecules ◽  
Side Chain Length ◽  
Dynamics Simulations ◽  
Chain Lengths ◽  
Polycarboxylate Ether ◽  
Diffusion Properties

Molecular dynamics simulations were carried out to study the conformations of polycarboxylate ether (PCE) superplasticizers with different side chain lengths in aqueous solution. For four types of PCE molecules—PCE1, PCE2, PCE3, and PCE4—the steric hindrance between the PCE molecules increased with increasing side chain length. The side chain length not only affects water mobility but also affects the distribution of water molecules in the system. Simulation results indicate that water molecules were trapped by the PCE molecules, reducing the diffusion properties. PCE molecules with long side chains have more water molecules probability around the main chain and fewer water molecules probability near the side chain. Microscopic-level knowledge of the interaction between superplasticizer and water molecules facilitates understanding of the performance of superplasticizers in cement systems.

Effect of side chain length on intrahelical interactions between carboxylate- and guanidinium-containing amino acids

Amino Acids ◽  
2014 ◽  
Vol 46 (8) ◽  
pp. 1867-1883 ◽  
Author(s):  
Hsiou-Ting Kuo ◽  
Po-An Yang ◽  
Wei-Ren Wang ◽  
Hao-Chun Hsu ◽  
Cheng-Hsun Wu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Chain Length ◽  
Side Chain ◽  
Side Chain Length

scholarly journals Effects of Amino Acid Side-Chain Length and Chemical Structure on Anionic Polyglutamic and Polyaspartic Acid Cellulose-Based Polyelectrolyte Brushes

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1789
Author(s):  
Dmitry Tolmachev ◽  
George Mamistvalov ◽  
Natalia Lukasheva ◽  
Sergey Larin ◽  
Mikko Karttunen
Keyword(s):  
Glutamic Acid ◽  
Chain Length ◽  
Chemical Structure ◽  
Side Chain ◽  
Side Chains ◽  
Side Chain Length ◽  
Polyelectrolyte Brushes ◽  
Grafting Density ◽  
The Difference ◽  
Cellulose Surface

We used atomistic molecular dynamics (MD) simulations to study polyelectrolyte brushes based on anionic α,L-glutamic acid and α,L-aspartic acid grafted on cellulose in the presence of divalent CaCl2 salt at different concentrations. The motivation is to search for ways to control properties such as sorption capacity and the structural response of the brush to multivalent salts. For this detailed understanding of the role of side-chain length, the chemical structure and their interplay are required. It was found that in the case of glutamic acid oligomers, the longer side chains facilitate attractive interactions with the cellulose surface, which forces the grafted chains to lie down on the surface. The additional methylene group in the side chain enables side-chain rotation, enhancing this effect. On the other hand, the shorter and more restricted side chains of aspartic acid oligomers prevent attractive interactions to a large degree and push the grafted chains away from the surface. The difference in side-chain length also leads to differences in other properties of the brush in divalent salt solutions. At a low grafting density, the longer side chains of glutamic acid allow the adsorbed cations to be spatially distributed inside the brush resulting in a charge inversion. With an increase in grafting density, the difference in the total charge of the aspartic and glutamine brushes disappears, but new structural features appear. The longer sides allow for ion bridging between the grafted chains and the cellulose surface without a significant change in main-chain conformation. This leads to the brush structure being less sensitive to changes in salt concentration.

scholarly journals Sterol side chain length and structure affect the clearance of chylomicron-like lipid emulsions in rats and mice

1998 ◽  
Vol 39 (2) ◽  
pp. 302-312 ◽  
Author(s):  
Ian J. Martins ◽  
Catherine Vilchèze ◽  
B-C. Mortimer ◽  
Robert Bittman ◽  
Trevor G. Redgrave
Keyword(s):  
Chain Length ◽  
Side Chain ◽  
Lipid Emulsions ◽  
Side Chain Length ◽  
Rats And Mice

Effect of the Side-Chain Length and NLO Properties of the N-ethyl-N,N,N-trialkylammonium Ionic Liquids – A DFT Study

2021 ◽  
pp. 116251
Author(s):  
M.A. Olea-Amezcua ◽  
J.E. Castellanos-Águila ◽  
H. HernÁndez-Cocoletzi ◽  
E. Ferreira ◽  
M. Trejo-Durán ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Chain Length ◽  
Dft Study ◽  
Side Chain ◽  
Side Chain Length ◽  
Nlo Properties
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