Related Experiment Video
Updated: May 7, 2026
09:42
Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Solvent interaction analysis of intrinsically disordered proteins in aqueous two-phase systems
Leonid Breydo1, Larissa M Mikheeva, Pedro P Madeira
1Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA. vuversky@health.usf.edu.
Molecular Biosystems
|September 28, 2013
Summary
Aqueous two-phase systems (ATPS) can reveal structural differences between proteins like alpha-synuclein and globular proteins. High polymer concentrations in ATPS mimic macromolecular crowding, impacting protein structure.
Area of Science:
- Biochemistry
- Biophysics
- Protein Science
Background:
- Proteins partition differently in aqueous two-phase systems (ATPS) based on their interactions with aqueous media.
- High polymer concentrations in ATPS mimic macromolecular crowding, a common cellular condition.
- Understanding protein behavior in crowded environments is crucial for cell biology.
Purpose of the Study:
- To investigate the use of ATPS for quantifying structural differences among proteins, including alpha-synuclein and its variants.
- To evaluate the structural consequences of high polymer concentrations and varying ionic compositions on proteins using ATPS.
- To explore the relationship between ATPS partitioning and macromolecular crowding effects on protein structure.
Main Methods:
- Utilized aqueous two-phase systems (ATPS) with varying ionic compositions.
- Employed circular dichroism (CD) spectroscopy to assess protein secondary and tertiary structures.
- Analyzed the partitioning behavior of alpha-synuclein, its variants, and globular proteins within the ATPS.
Main Results:
- Protein partitioning in ATPS effectively differentiates structural characteristics between alpha-synuclein, its variants, and globular proteins.
- High polymer concentrations in ATPS, mimicking macromolecular crowding, induced measurable structural changes in proteins.
- Ionic composition of the ATPS significantly influenced protein partitioning and structural stability.
Conclusions:
- ATPS is a valuable tool for probing subtle structural differences in proteins, particularly in the context of macromolecular crowding.
- Protein structural integrity is sensitive to both polymer concentration and ionic environment in aqueous solutions.
- This study provides insights into protein behavior under conditions relevant to the cellular interior.
Related Concept Videos
02:05Entropy and Solvation
The process of surrounding a solute with solvent is called solvation. It involves evenly distributing the solute within the solvent. The rule of thumb for determining a solvent for a given compound is that like dissolves like. A good solvent has molecular characteristics similar to those of the compound to be dissolved. For example, polar solutions dissolve polar solutes, and apolar solvents dissolve apolar solutes. A polar solvent is a solvent that has a high dielectric constant (ϵ ≥ 15); an...
01:09Theories of Dissolution: The Danckwerts' Model and Interfacial Barrier Model
Various dissolution theories provide insight into the factors that influence the dissolution rate. Danckwerts' Model suggests that turbulence, rather than a stagnant layer, characterizes the dissolution medium at the solid-liquid interface. In this model, the agitated solvent contains macroscopic packets that move to the interface via eddy currents, facilitating the absorption and delivery of the drug to the bulk solution. The regular replenishment of solvent packets maintains the concentration...
03:13Intermolecular Forces
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen bonds, and dispersion...
02:28Intermolecular Forces in Solutions
The formation of a solution is an example of a spontaneous process, a process that occurs under specified conditions without energy from some external source.
When the strengths of the intermolecular forces of attraction between solute and solvent species in a solution are no different than those present in the separated components, the solution is formed with no accompanying energy change. Such a solution is called an ideal solution. A mixture of ideal gases (or gases such as helium and argon,...
When the strengths of the intermolecular forces of attraction between solute and solvent species in a solution are no different than those present in the separated components, the solution is formed with no accompanying energy change. Such a solution is called an ideal solution. A mixture of ideal gases (or gases such as helium and argon,...
03:00Solubility
Solution, Solubility, and Solubility Equilibrium
A solution is a homogeneous mixture composed of a solvent, the major component, and a solute, the minor component. The physical state of a solution—solid, liquid, or gas—is typically the same as that of the solvent. Solute concentrations are often described with qualitative terms such as dilute (of relatively low concentration) and concentrated (of relatively high concentration).
In a solution, the solute particles (molecules, atoms, and/or ions)...
A solution is a homogeneous mixture composed of a solvent, the major component, and a solute, the minor component. The physical state of a solution—solid, liquid, or gas—is typically the same as that of the solvent. Solute concentrations are often described with qualitative terms such as dilute (of relatively low concentration) and concentrated (of relatively high concentration).
In a solution, the solute particles (molecules, atoms, and/or ions)...
02:21Chemical and Solubility Equilibria
The free energy change associated with dissolving a solute in a liter of solvent is called the free energy of a solution, ΔGsolution. The overall ΔGsolution is expressed as the balance of ΔGinteraction against the always-favorable free-energy of mixing, ΔGmixing. Solution formation is favorable if ΔGsolution is less than zero, whereas it is unfavorable if ΔGsolution is greater than zero. In short, for a solution to form and complete dissolution to take place, the Gibbs energy change must be...