Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Protein Folding

Protein Folding

Protein Folding

Protein Folding

Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to its biological function. Interactions between its constituent amino acids guide protein folding, and hence the protein structure is primarily dependent on its amino acid sequence.
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...

Protein Organization

Protein Organization

Proteins are polymers of amino acid residues. They are versatile and responsible for different cellular functions, including DNA replication, molecular transport, catalysis, and structural support. Proteins have a hierarchical structure comprising at least three levels of organization: primary, secondary, and tertiary structure. Some large proteins have a quaternary structure where individual protein subunits are linked together.
The primary structure of a protein is its amino acid sequence.

Protein Organization

Protein Organization

Protein and Protein Structure

Protein and Protein Structure

Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective. They may serve in transport, storage, or membranes; or they may be toxins or enzymes. Their structures, like their functions, vary greatly. They are all, however, amino acid polymers arranged in a linear sequence.
A protein's shape is critical to its function. For example, an enzyme can...

Noncovalent Attractions in Biomolecules

Noncovalent Attractions in Biomolecules

Noncovalent attractions are associations within and between molecules that influence the shape and structural stability of complexes. These interactions differ from covalent bonding in that they do not involve sharing of electrons.
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,...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Self-Assembling Peptides, Conjugates, and Mimics: A Versatile Platform for Materials and Beyond.

Accounts of chemical research·2025

Same author

Manipulation of coacervate droplets with an electric field.

Proceedings of the National Academy of Sciences of the United States of America·2022

Same author

Comparing Solvophobic and Multivalent Induced Collapse in Polyelectrolyte Brushes.

ACS macro letters·2022

Same author

Protein Encapsulation via Polypeptide Complex Coacervation.

ACS macro letters·2022

Same author

Interfacial Tension of Polyelectrolyte Complex Coacervate Phases.

ACS macro letters·2022

Same author

Correction: Ntakolia et al. An Explainable Machine Learning Approach for COVID-19's Impact on Mood States of Children and Adolescents during the First Lockdown in Greece. <i>Healthcare</i> 2022, <i>10</i>, 149.

Healthcare (Basel, Switzerland)·2022

Search research articles

Related Experiment Video

Updated: May 17, 2026

Detecting and Characterizing Protein Self-Assembly In Vivo by Flow Cytometry

Detecting and Characterizing Protein Self-Assembly In Vivo by Flow Cytometry

Published on: July 17, 2019

Thermodynamic characterization of polypeptide complex coacervation.

Dimitrios Priftis¹, Nicolas Laugel, Matthew Tirrell

¹Department of Bioengineering, University of California, Berkeley, California 94720, United States. dpriftis@uchicago.edu

Langmuir : the ACS Journal of Surfaces and Colloids

|October 23, 2012

Summary

Polypeptide complex coacervation, driven by entropy, involves soluble ion pairing followed by insoluble aggregation. This process is sensitive to salt concentration, pH, and polymer properties, as revealed by isothermal titration calorimetry.

More Related Videos

Single-Molecule Measurement of Protein Interaction Dynamics Within Biomolecular Condensates

Single-Molecule Measurement of Protein Interaction Dynamics Within Biomolecular Condensates

Published on: January 5, 2024

Assembly and Characterization of Polyelectrolyte Complex Micelles

Assembly and Characterization of Polyelectrolyte Complex Micelles

Published on: March 2, 2020

Related Experiment Videos

Last Updated: May 17, 2026

Detecting and Characterizing Protein Self-Assembly In Vivo by Flow Cytometry

Detecting and Characterizing Protein Self-Assembly In Vivo by Flow Cytometry

Published on: July 17, 2019

Single-Molecule Measurement of Protein Interaction Dynamics Within Biomolecular Condensates

Single-Molecule Measurement of Protein Interaction Dynamics Within Biomolecular Condensates

Published on: January 5, 2024

Assembly and Characterization of Polyelectrolyte Complex Micelles

Assembly and Characterization of Polyelectrolyte Complex Micelles

Published on: March 2, 2020

Area of Science:

Biophysics
Polymer Science
Physical Chemistry

Background:

Polypeptide complex coacervation is a phase separation phenomenon crucial in biological systems.
Understanding the thermodynamics of this process is key to controlling material properties.

Purpose of the Study:

To elucidate the thermodynamic driving forces behind polypeptide complex coacervation.
To investigate the influence of environmental factors and polymer characteristics on coacervation.

Main Methods:

Isothermal titration calorimetry (ITC) to measure binding thermodynamics.
Turbidity measurements and optical microscopy to observe complex formation and aggregation.
Empirical extension of a binding model to describe the two-step coacervation process.

Main Results:

Complex coacervation is an endothermic, entropy-driven process.
Increased salt concentration reduces interaction propensity and coacervate yield.
pH significantly impacts functional group ionization and complex formation.
Higher polymer concentrations and chain lengths promote coacervation.

Conclusions:

Coacervation proceeds via distinct ion pairing and aggregation steps.
Thermodynamic parameters like heat capacity change can be determined.
The study provides a quantitative understanding of polypeptide coacervation, applicable to biomaterials and soft matter physics.