Thermodynamic study of the acid denaturation of barnase and its dependence on ionic strength: Evidence for residual electrostatic interactions in the acid/thermally denatured state

Biochemistry ◽  
1994 ◽  
Vol 33 (29) ◽  
pp. 8826-8832 ◽  
Author(s):  
Mikael Oliveberg ◽  
Stephane Vuilleumier ◽  
Alan R. Fersht
Keyword(s):  
Ionic Strength ◽  
Electrostatic Interactions ◽  
Thermodynamic Study ◽  
Denatured State ◽  
Acid Denaturation ◽  
Dependence On Ionic Strength

Thermodynamic Study for the Protonation of Branched Poly(ethylenimine) in NaCl(aq) and Its Dependence on Ionic Strength

2007 ◽  
Vol 52 (1) ◽  
pp. 279-285 ◽  
Author(s):  
Francesco Crea ◽  
Pasquale Crea ◽  
Alessandro De Robertis ◽  
Silvio Sammartano
Keyword(s):  
Ionic Strength ◽  
Thermodynamic Study ◽  
Dependence On Ionic Strength

scholarly journals Anomalous Salt Dependence Reveals an Interplay of Attractive and Repulsive Electrostatic Interactions in α-synuclein Fibril Formation

QRB Discovery ◽  
2020 ◽  
Vol 1 ◽  
Author(s):  
Ricardo Gaspar ◽  
Mikael Lund ◽  
Emma Sparr ◽  
Sara Linse
Keyword(s):  
Ionic Strength ◽  
Electrostatic Interactions ◽  
Intrinsically Disordered Protein ◽  
Lipid Vesicles ◽  
Intrinsically Disordered ◽  
Catalytic Surfaces ◽  
Disordered Protein ◽  
Salt Dependence ◽  
Fluorescence Measurements ◽  
The One

Abstractα-Synuclein (α-syn) is an intrinsically disordered protein with a highly asymmetric charge distribution, whose aggregation is linked to Parkinson’s disease. The effect of ionic strength was investigated at mildly acidic pH (5.5) in the presence of catalytic surfaces in the form of α-syn seeds or anionic lipid vesicles using thioflavin T fluorescence measurements. Similar trends were observed with both surfaces: increasing ionic strength reduced the rate of α-syn aggregation although the surfaces as well as α-syn have a net negative charge at pH 5.5. This anomalous salt dependence implies that short-range attractive electrostatic interactions are critical for secondary nucleation as well as heterogeneous primary nucleation. Such interactions were confirmed in Monte Carlo simulations of α-syn monomers interacting with surface-grafted C-terminal tails, and found to be weakened in the presence of salt. Thus, nucleation of α-syn aggregation depends critically on an attractive electrostatic component that is screened by salt to the extent that it outweighs the screening of the long-range repulsion between negatively charged monomers and negative surfaces. Interactions between the positively charged N-termini of α-syn monomers on the one hand, and the negatively C-termini of α-syn on fibrils or vesicles surfaces on the other hand, are thus critical for nucleation.

scholarly journals Adjacent cationic–aromatic sequences yield strong electrostatic adhesion of hydrogels in seawater

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Hailong Fan ◽  
Jiahui Wang ◽  
Zhen Tao ◽  
Junchao Huang ◽  
Ping Rao ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Electrostatic Interaction ◽  
Electrostatic Interactions ◽  
Saline Water ◽  
Aromatic Amino Acids ◽  
High Ionic Strength ◽  
Polymer Materials ◽  
Specific Sequence ◽  
Charged Surfaces ◽  
Π Complex

Abstract Electrostatic interaction is strong but usually diminishes in high ionic-strength environments. Biosystems can use this interaction through adjacent cationic–aromatic amino acids sequence of proteins even in a saline medium. Application of such specific sequence to the development of cationic polymer materials adhesive to negatively charged surfaces in saline environments is challenging due to the difficulty in controlling the copolymer sequences. Here, we discover that copolymers with adjacent cation–aromatic sequences can be synthesized through cation–π complex-aided free-radical polymerization. Sequence controlled hydrogels from diverse cation/aromatic monomers exhibit fast, strong but reversible adhesion to negatively charged surfaces in seawater. Aromatics on copolymers are found to enhance the electrostatic interactions of their adjacent cationic residues to the counter surfaces, even in a high ionic-strength medium that screens the electrostatic interaction for common polyelectrolytes. This work opens a pathway to develop adhesives using saline water.

Acid−Base Equilibrium Constants for Glycine in NaClO4, KCl, and KBr at 298 K. Dependence on Ionic Strength

1998 ◽  
Vol 43 (5) ◽  
pp. 876-879 ◽  
Author(s):  
P. Alonso ◽  
J. L. Barriada ◽  
P. Rodríguez ◽  
I. Brandariz ◽  
M. E. Sastre de Vicente
Keyword(s):  
Ionic Strength ◽  
Equilibrium Constants ◽  
Acid Base ◽  
Base Equilibrium ◽  
Acid Base Equilibrium ◽  
Dependence On Ionic Strength
Sign in / Sign up

Export Citation Format

Share Document