Related Experiment Video
Updated: Feb 25, 2026

Sedimentation Equilibrium of a Small Oligomer-forming Membrane Protein: Effect of Histidine Protonation on Pentameric Stability
Published on: April 2, 2015
Evidence for cooperative Na+ and Cl- binding by strongly hydrated l-proline
Olga A Dmitrieva1, Marina V Fedotova1, Richard Buchner2
1G.A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Akademicheskaya st. 1, 153045 Ivanovo, Russian Federation. hebrus@mail.ru.
Abstract:
In nature the amino acid l-proline (Pro) is a ubiquitous and highly effective osmolyte protecting cells against osmotic stress. To understand this effect knowledge of the hydration of Pro and its interactions with dissolved salts is essential. We studied these properties by combining statistical mechanics and broadband dielectric spectroscopy and found that Pro remains strongly hydrated up to high amino-acid concentrations. This is also the case upon NaCl addition to a 0.6 M Pro solution. Here, additionally a Pro·NaCl aggregate is formed with a stability constant of K° ≈ 0.95…1.25 M-1, where Na+ and Cl- cooperatively bind to adjacent carboxylate-oxygen and ammonium-hydrogen atoms, respectively.
More Related Videos
10:31Residue-Specific Exchange of Proline by Proline Analogs in Fluorescent Proteins: How "Molecular Surgery" of the Backbone Affects Folding and Stability
Published on: February 3, 2022
05:50Pharmacophore Modeling for Targets with Extensive Ligand Libraries: A Case Study on SARS-CoV-2 Mpro
Published on: September 26, 2025
Related Concept Videos
Ligand Binding Sites
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
Protein Folding
Metal-Ligand Bonds
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
Amino acids
Noncovalent Attractions in Biomolecules
Four types of noncovalent interactions are hydrogen bonds, van der Waals forces, ionic bonds, and hydrophobic interactions.
Hydrogen bonding results from the electrostatic attraction of a hydrogen atom covalently bonded to a strong-electronegative atom like oxygen,...
Cooperative Allosteric Transitions