scholarly journals A minireview on the perturbation effects of polar groups to direct nanoscale hydrophobic interaction and amphiphilic peptide assembly

RSC Advances ◽  
2021 ◽  
Vol 11 (46) ◽  
pp. 28667-28673
Author(s):  
Feiyi Zhang ◽  
Lanlan Yu ◽  
Wenbo Zhang ◽  
Lei Liu ◽  
Chenxuan Wang
Keyword(s):  
Hydrophobic Interaction ◽  
Driving Force ◽  
Peptide Assembly ◽  
Supramolecular Architectures ◽  
Polar Groups ◽  
Amphiphilic Peptide

Hydrophobic interaction provides the essential driving force for creating diverse native and artificial supramolecular architectures.

scholarly journals Hydrophobic Interaction: A Promising Driving Force for the Biomedical Applications of Nucleic Acids

2020 ◽  
Vol 7 (16) ◽  
pp. 2001048 ◽  
Author(s):  
Fan Xiao ◽  
Zhe Chen ◽  
Zixiang Wei ◽  
Leilei Tian
Keyword(s):  
Nucleic Acids ◽  
Hydrophobic Interaction ◽  
Driving Force ◽  
Biomedical Applications

Desorptive behavior of chlorophenols in contaminated soils

1996 ◽  
Vol 33 (6) ◽  
pp. 263-270 ◽  
Author(s):  
C. N. You ◽  
J. C. Liu
Keyword(s):  
Soil Properties ◽  
Soil Water ◽  
Anionic Surfactant ◽  
Hydrophobic Interaction ◽  
Contaminated Soils ◽  
Driving Force ◽  
Water System ◽  
Ionic Surfactant ◽  
Effects Of Ph

A study was conducted to assess the desorptive behavior of chlorophenols in contaminated soils. Two soils spiked with three types of chlorophenols, i.e., 2,6-dichlorophenol (DCP), 2,4,6-trichlorophenol (TCP), and pentachlorophenol (PCP), respectively, were examined. The effects of pH, methanol, surfactants, and soil properties were investigated. Amount of three chlorophenols desorbed from soils increased with increasing pH. Deprotonated chlorophenols were more mobile than their conjugate acids. When methanol was added to the soil-water system, the amount of chlorophenols desorbed increased. The desorption of PCP was enhanced in the presence of anionic surfactant, SDS. However, when non-ionic surfactant, TX-100, was present, the desorption of PCP decreased. The effects of pH and surfactants on desorptive behavior of chlorophenols were most significant on PCP. Generally, the amount of chlorophenol adsorption deceased in the order PCP > TCP > DCP. Hydrophobic interaction was found to be the major driving force of adsorption reactions. It was therefore proposed that hydrophobicity of chlorophenols is an important factor controlling their desorptive behavior.

Hydrophobic interaction between the bile acids and long-chain alkyltrimethylammonium ions: A model for cholesterol-lipid interaction

1977 ◽  
Vol 30 (2) ◽  
pp. 335 ◽  
Author(s):  
DG Oakenfull ◽  
DE Fenwick
Keyword(s):  
Free Energy ◽  
Bile Acid ◽  
Bile Acids ◽  
Hydrophobic Interaction ◽  
Alkyl Chain ◽  
Ion Pair ◽  
Oh Groups ◽  
Polar Groups ◽  
Methylene Group ◽  
Long Chain

Ion-pair association constants (K) for long-chain alkyltrimethylammonium salts of the bile acids have been measured conductometrically at 25°C in 0.1 mole fraction ethanol-water. The free energy of ion-pair formation (ΔG°ip = -RT ln K) was separated into its electrostatic and hydrophobic components by examining the effect of alkyl chain length on ΔG°ip. The electrostatic contribution was the same for each bile acid and agreed with the value previously obtained for long-chain alkyltrimethyl-ammonium carboxylate ion pairs under the same conditions. The hydrophobic contribution depended on the structure of the bile acid and varied linearly with the number of OH groups. (There are no significant attractive forces between non-polar groups in water. Hydrophobic interaction is the tendency of non-polar groups to associate because this minimizes their energetically unfavourable contact with water.) Our results support current theories of hydrophobic interaction and give an indication of the extent of the effect of neighbouring polar groups on hydrophobic interaction. Extrapolation to zero OH groups gave an estimate of the free energy of hydrophobic interaction (ΔG°HI) between an alkyl chain and a cholesterol analogue (a steroid ring system with a single polar substituent). This value of ΔG°HI was -2.77 kJ mol-1 per methylene group compared with -2.24 kJ mol-1 per methylene group for hydrophobic interaction between two alkyl chains. (The small difference is explained by the greater number of water molecules displaced in an alkyl-steroid contact than in an alkyl-alkyl contact.) This result conflicts with claims made by other workers that the steroid-alkyl interaction is weak, or that cholesterol is less hydrophobic than its structure indicates.

scholarly journals Heterogeneous Impacts of Protein-Stabilizing Osmolytes on Hydrophobic Interaction

2018 ◽  
Author(s):  
Mrinmoy Mukherjee ◽  
Jagannath Mondal
Keyword(s):  
Hydrophobic Interaction ◽  
Driving Force ◽  
Hydrophobic Interactions ◽  
Interaction Analysis ◽  
Protein Sequences ◽  
Methyl Groups ◽  
Complex Interplay ◽  
Diverse Range ◽  
Hydrophobic Collapse ◽  
Preferential Binding

AbstractOsmolytes’ mechanism of protecting proteins against denaturation is a longstanding puzzle, further complicated by the complex diversities inherent in protein sequences. An emergent approach in understanding osmolytes’ mechanism of action towards biopolymer has been to investigate osmolytes’ interplay with hydrophobic interaction, the major driving force of protein folding. However, the crucial question is whether all these protein-stabilizing osmolytes display a single unified mechanism towards hydrophobic interactions. By simulating the hydrophobic collapse of a macromolecule in aqueous solutions of two such osmoprotectants, Glycine and Trimethyl N-oxide (TMAO), both of which are known to stabilize protein’s folded conformation, we here demonstrate that these two osmolytes can impart mutually contrasting effects towards hydrophobic interaction. While TMAO preserves its protectant nature across diverse range of polymer-osmolyte interactions, glycine is found to display an interesting cross-over from being a protectant at weaker polymer-osmolyte interaction to a denaturant of hydrophobicity at stronger polymer-osmolyte interactions. A preferential-interaction analysis reveals that a subtle balance of conformation-dependent exclusion/binding of osmolyte molecules from/to the macromolecule holds the key to overall heterogenous behavior. Specifically, TMAO’s consistent stabilization of collapsed configuration of macromolecule is found to be a result of TMAO’s preferential binding to polymer via hydrophobic methyl groups. However, polar Glycine’s cross-over from being a protectant to denaturant across polymer-osmolyte interaction is rooted in its switch from preferential exclusion to preferential binding to the polymer with increasing interaction. Overall, by highlighting the complex interplay of osmolytes with hydrophobic interaction, this work puts forward the necessity of quantitative categorization of osmolytes’ action in protein.

scholarly journals Chirality Effects in Peptide Assembly Structures

2021 ◽  
Vol 9 ◽  
Author(s):  
Yongfang Zheng ◽  
Kejing Mao ◽  
Shixian Chen ◽  
Hu Zhu
Keyword(s):  
Amino Acid ◽  
Cyclic Peptide ◽  
Building Blocks ◽  
External Factors ◽  
Medical Applications ◽  
Amino Acid Residues ◽  
Peptide Assembly ◽  
Supramolecular Architectures ◽  
Peptide Mixtures ◽  
Regulatory Effects

Peptide assembly structures have been widely exploited in fabricating biomaterials that are promising for medical applications. Peptides can self-organize into various highly ordered supramolecular architectures, such as nanofibril, nanobelt, nanotube, nanowire, and vesicle. Detailed studies of the molecular mechanism by which these versatile building blocks assemble can guide the design of peptide architectures with desired structure and functionality. It has been revealed that peptide assembly structures are highly sequence-dependent and sensitive to amino acid composition, the chirality of peptide and amino acid residues, and external factors, such as solvent, pH, and temperature. This mini-review focuses on the regulatory effects of chirality alteration on the structure and bioactivity of linear and cyclic peptide assemblies. In addition, chiral self-sorting and co-assembly of racemic peptide mixtures were discussed.

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

The nucleation of cavities at grain boundaries

1987 ◽  
Vol 45 ◽  
pp. 288-291
Author(s):  
P. J. Goodhew
Keyword(s):  
Surface Tension ◽  
Surface Energy ◽  
Grain Boundaries ◽  
Radiation Damage ◽  
Impurity Concentration ◽  
Driving Force ◽  
Nucleation And Growth ◽  
Phase Boundaries ◽  
Cavity Nucleation ◽  
Spherical Bubble

Cavity nucleation and growth at grain and phase boundaries is of concern because it can lead to failure during creep and can lead to embrittlement as a result of radiation damage. Two major types of cavity are usually distinguished: The term bubble is applied to a cavity which contains gas at a pressure which is at least sufficient to support the surface tension (2g/r for a spherical bubble of radius r and surface energy g). The term void is generally applied to any cavity which contains less gas than this, but is not necessarily empty of gas. A void would therefore tend to shrink in the absence of any imposed driving force for growth, whereas a bubble would be stable or would tend to grow. It is widely considered that cavity nucleation always requires the presence of one or more gas atoms. However since it is extremely difficult to prepare experimental materials with a gas impurity concentration lower than their eventual cavity concentration there is little to be gained by debating this point.

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