Solvent accessibility and hydrophobicity in the adsorption of alkylammonium cations at air/water and Hg/water interfaces. Part II. Behavior at the Hg/water interface in relation to hydrophobic interactions

1981 ◽  
Vol 59 (13) ◽  
pp. 1987-1997 ◽  
Author(s):  
B. E. Conway ◽  
F. Rocheleau
Keyword(s):  
Aqueous Solutions ◽  
Surface Potential ◽  
Surface Pressure ◽  
Hydrophobic Interactions ◽  
Solvent Accessibility ◽  
Adsorption Behavior ◽  
Water Interface ◽  
3 Dimensional ◽  
Electrode Potentials ◽  
Air Water Interface

The adsorption behavior of a series of n-propylammonium ions in which the N+ center has varying accessibility to the solvent, and hence the ions exhibit varying hydrophobicity, is examined at the Hg/H2O interface at various electrode potentials. With the most hydrophobic ion, (n-Pr)4N+, attractive interactions arise in the interphase. An attempt is made to explain this behavior in terms of Gurney hydration co-sphere sharing effects which are significant in 3-dimensional aqueous solutions of R4N+ salts.The surface pressure behavior and Esin and Markov effects are also evaluated.Comparisons are made with the adsorption and surface potential results reported in Part I for the air/water interface.

Solvent accessibility and hydrophobicity in the adsorption of alkylammonium cations at air/water and Hg/water interfaces. Part 1. Behavior at the air/water interface in relation to hydration properties

1981 ◽  
Vol 59 (13) ◽  
pp. 1978-1986 ◽  
Author(s):  
R. Bennes ◽  
B. E. Conway
Keyword(s):  
Surface Potential ◽  
Hydrophobic Interactions ◽  
Solvent Accessibility ◽  
Water Interface ◽  
Ion Distribution ◽  
Progressive Change ◽  
Hydration Properties ◽  
Air Water Interface ◽  
Electrostatic And Hydrophobic Interactions

By means of adsorption and surface-potential studies on a series of R4−nN+Hn perchlorates at the air/water interface, the role of hydrophobic and hydrophilic interaction in the adsorption and ion distribution of these salts near the air/water interface is examined. While the adsorption of the alkylamine ions increases as n decreases from three to zero, inclusive, the surface-potential change accompanying the adsorption decreases. This effect is interpreted in terms of opposing hydrophilic, electrostatic and hydrophobic interactions between the organic ion and water near the liquid surface, leading to a progressive change of double-layer ion distribution. In Part II, comparative studies of the same series of compounds at the Hg/water interface are reported.

scholarly journals Characterization of the lipid-binding domain of the Plasmodium falciparum CTP:phosphocholine cytidylyltransferase through synthetic-peptide studies

2003 ◽  
Vol 375 (3) ◽  
pp. 653-661 ◽  
Author(s):  
Marie-Pierre LARVOR ◽  
Rachel CERDAN ◽  
Catherine GUMILA ◽  
Luc MAURIN ◽  
Patrick SETA ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Pressure ◽  
Hydrophobic Interactions ◽  
Lipid Binding ◽  
Binding Domain ◽  
Helical Conformation ◽  
Initial Surface ◽  
Water Interface ◽  
Ctp:Phosphocholine Cytidylyltransferase ◽  
Air Water Interface

Phospholipid biosynthesis plays a key role in malarial infection and is regulated by CCT (CTP:phosphocholine cytidylyltransferase). This enzyme belongs to the group of amphitropic proteins which are regulated by reversible membrane interaction. To assess the role of the putative membrane-binding domain of Plasmodium falciparum CCT (PfCCT), we synthesized three peptides, K21, V20 and K54 corresponding to residues 274–294, 308–327 and 274–327 of PfCCT respectively. Conformational behaviour of the peptides, their ability to bind to liposomes and to destabilize lipid bilayers, and their insertion properties were investigated by different biophysical techniques. The intercalation mechanisms of the peptides were refined further by using surface-pressure measurements on various monolayers at the air/water interface. In the present study, we show that the three studied peptides are able to bind to anionic and neutral phospholipids, and that they present an α-helical conformation upon lipid binding. Peptides V20 and the full-length K54 intercalate their hydrophobic parts into an anionic bilayer and, to a lesser extent, a neutral one for V20. Peptide K21 interacts only superficially with both types of phospholipid vesicles. Adsorption experiments performed at the air/water interface revealed that peptide K54 is strongly surface-active in the absence of lipid. Peptide V20 presents an atypical behaviour in the presence of phosphatidylserine. Whatever the initial surface pressure of a phosphatidylserine film, peptide V20 and phosphatidylserine entities seem linked together in a special organization involving electrostatic and hydrophobic interactions. We showed that PfCCT presents different lipid-dependence properties from other studied CCTs. Although the lipid-binding domain seems to be located in the C-terminal region of the enzyme, as with the mammalian counterpart, the membrane anchorage, which plays a key role in the enzyme regulation, is driven by two α-helices, which behave differently from one another.

scholarly journals Surface Potential of the Air/Water Interface

2020 ◽  
Vol 69 (6) ◽  
pp. 519-528 ◽  
Author(s):  
Cuong V. Nguyen ◽  
Hiromichi Nakahara ◽  
Chi M. Phan
Keyword(s):  
Surface Potential ◽  
Water Interface ◽  
Air Water Interface
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