scholarly journals From molecular modules to modular materials

2004 ◽  
Vol 76 (10) ◽  
pp. 1847-1867 ◽  
Author(s):  
D. G. Kurth ◽  
Shaoqin Liu ◽  
D. Volkmer
Keyword(s):  
Hydrophobic Interactions ◽  
Current Understanding ◽  
Structural Components ◽  
Molecular Materials ◽  
Electrostatic And Hydrophobic Interactions

The combination of metallosupramolecular modules (MEMOs) as functional and amphiphiles as structural components is presented in detail to illustrate our current understanding of encapsulation using surfactants, lipids, and dendrimers. The simplicity of fabrication and the availability of the starting components allow this technique as an attractive tool to create new nanoscale molecular materials. The interaction of amphiphiles and MEMOs occurs spontaneously and is driven by the release of counterions as well as electrostatic and hydrophobic interactions.

Interaction of sulphone based reactive dyes with cationic surfactant: a spectroscopic and conductometric study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Misbah Iram ◽  
Hamadia Sultana ◽  
Muhammad Usman ◽  
Bazgha Ahmad ◽  
Nadia Akram ◽  
...  
Keyword(s):  
Strong Interaction ◽  
Cetyltrimethylammonium Bromide ◽  
Hydrophobic Interactions ◽  
Reactive Dyes ◽  
Micellar System ◽  
Palisade Layer ◽  
Micellar Systems ◽  
Gibbs Energies ◽  
Electrostatic And Hydrophobic Interactions ◽  
Conductometric Study

Abstract Interaction of sulphone based reactive dyes, designated as dye-1 and dye-2, with cationic micellar system of cetyltrimethylammonium bromide (CTAB), has been investigated by spectroscopic and conductometeric measurements. Efficiency of the selected micellar systems is assessed by the values of binding constant (K b ), partition coefficient (K x ) and respective Gibbs energies. Critical micelle concentration (CMC) of surfactant, electrostatic and hydrophobic interactions as well as polarity of the medium plays significant role in this phenomenon. The negative values of Gibbs energies of binding (∆G b ) and partition (∆G p ) predicts the feasibility and spontaneity of respective processes. Similarly negative values of ∆G m and ∆H m and positive values of ∆S m , calculated from conductometeric data, further, revealed the exothermicity, spontaneity and, thus, stability of system. The results, herein, have disclosed the strong interaction between dye and surfactant molecules. The dye-2 has been observed to be solubilized to greater extent, as compared to dye 1, due to strong interaction ith hydrophiles of CTAB and accommodation of its molecules in palisade layer of micelle closer to the micelle/water interface.

scholarly journals The contribution of hydrophobic residues in the pore-forming region of the ryanodine receptor channel to block by large tetraalkylammonium cations and Shaker B inactivation peptides

2012 ◽  
Vol 140 (3) ◽  
pp. 325-339 ◽  
Author(s):  
Sammy A. Mason ◽  
Cedric Viero ◽  
Joanne Euden ◽  
Mark Bannister ◽  
Duncan West ◽  
...  
Keyword(s):  
Ryanodine Receptor ◽  
Hydrophobic Interactions ◽  
Structural Information ◽  
Dissociation Rate ◽  
Structural Components ◽  
Hydrophobic Residues ◽  
K Channels ◽  
New Information ◽  
Tetraalkylammonium Cations ◽  
Cytosolic Side

Although no high-resolution structural information is available for the ryanodine receptor (RyR) channel pore-forming region (PFR), molecular modeling has revealed broad structural similarities between this region and the equivalent region of K+ channels. This study predicts that, as is the case in K+ channels, RyR has a cytosolic vestibule lined with predominantly hydrophobic residues of transmembrane helices (TM10). In K+ channels, this vestibule is the binding site for blocking tetraalkylammonium (TAA) cations and Shaker B inactivation peptides (ShBPs), which are stabilized by hydrophobic interactions involving specific residues of the lining helices. We have tested the hypothesis that the cytosolic vestibule of RyR fulfils a similar role and that TAAs and ShBPs are stabilized by hydrophobic interactions with residues of TM10. Both TAAs and ShBPs block RyR from the cytosolic side of the channel. By varying the composition of TAAs and ShBPs, we demonstrate that the affinity of both species is determined by their hydrophobicity, with variations reflecting alterations in the dissociation rate of the bound blockers. We investigated the role of TM10 residues of RyR by monitoring block by TAAs and ShBPs in channels in which the hydrophobicity of individual TM10 residues was lowered by alanine substitution. Although substitutions changed the kinetics of TAA interaction, they produced no significant changes in ShBP kinetics, indicating the absence of specific hydrophobic sites of interactions between RyR and these peptides. Our investigations (a) provide significant new information on both the mechanisms and structural components of the RyR PFR involved in block by TAAs and ShBPs, (b) highlight important differences in the mechanisms and structures determining TAA and ShBP block in RyR and K+ channels, and (c) demonstrate that although the PFRs of these channels contain analogous structural components, significant differences in structure determine the distinct ion-handling properties of the two species of channel.

scholarly journals Interaction of caldesmon with phospholipids

1993 ◽  
Vol 291 (2) ◽  
pp. 403-408 ◽  
Author(s):  
E A Czuryło ◽  
J Zborowski ◽  
R Dabrowska
Keyword(s):  
Fluorescence Spectroscopy ◽  
Hydrophobic Interactions ◽  
Tryptophan Fluorescence ◽  
Terminal Part ◽  
Strong Binding ◽  
Terminal Fragment ◽  
Electrostatic And Hydrophobic Interactions ◽  
The Stability

The interaction of caldesmon with liposomes composed of various phospholipids has been examined by tryptophan fluorescence spectroscopy. The results indicate that caldesmon makes its strongest complex with phosphatidylserine (PS) vesicles (Kass. = 1.45 x 10(5) M-1). Both electrostatic and hydrophobic interactions contribute to the stability of this complex. The site for strong binding of PS seems to be located in the N-terminal part of the 34 kDa C-terminal fragment of caldesmon. Binding of PS at this site results in displacement of calmodulin from its complex with caldesmon.

Contribution of electrostatic and hydrophobic interactions to the adsorption of proteins by aluminium-containing adjuvants

Vaccine ◽  
1995 ◽  
Vol 13 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Ragheb H. Al-Shakhshir ◽  
Fred E. Regnier ◽  
Joe L. White ◽  
Stanley L. Hem
Keyword(s):  
Hydrophobic Interactions ◽  
Electrostatic And Hydrophobic Interactions

The Adsorption Mechanism of Sodium Lignosulfonate on Al2O3 Particle in the Aqueous Solution

2012 ◽  
Vol 550-553 ◽  
pp. 1120-1123
Author(s):  
Rong Li ◽  
Dong Jie Yang ◽  
Wen Yuan Guo ◽  
Xue Qing Qiu
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bond ◽  
Driving Force ◽  
Adsorption Mechanism ◽  
Hydrophobic Interactions ◽  
Adsorption Properties ◽  
Sodium Lignosulfonate ◽  
Ph Values ◽  
Electrostatic And Hydrophobic Interactions ◽  
Monolayer Coverage

The adsorption properties of sodium lignosulfonate (SL) on Al2O3 particles under different pH values have been investigated. Results show that at low pHs, SL adsorbs on the Al2O3 particles in the form of aggregate as dosage of SL increases; at high pHs, the adsorption is approximately monolayer coverage. With pH values ranging from 3 to 11, the adsorption results are found to be not significantly affected by the addition of urea, ruling out the hydrogen bond as the controlling factor. The paper demonstrates that the main driving force of adsorption is considered as the synergistic effect of electrostatic and hydrophobic interactions when pH pHIEP with additives of Na2SO4 and NaCl.

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