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Updated: Aug 14, 2025
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Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
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Phase-Separation Propensity of Non-ionic Amino Acids in Peptide-Based Complex Coacervation Systems
Yuto Akahoshi1,2, Hiroka Sugai1,2, Masahiro Mimura1,2
1Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki305-8573, Japan.
Biomacromolecules
|January 14, 2023
Summary
Researchers developed a new method to quantify how non-ionic amino acids affect protein liquid-liquid phase separation (LLPS). They found that while most hydrophobic amino acids inhibit LLPS, aromatic ones surprisingly promote it due to DNA interactions.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Understanding protein liquid-liquid phase separation (LLPS) is key to cellular compartmentalization and protocell formation.
- The molecular grammar dictating LLPS is not fully understood, especially the role of specific amino acids.
Purpose of the Study:
- To create a quantitative index for the "phase-separation propensity" of non-ionic amino acids.
- To investigate the influence of non-ionic amino acids on peptide-nucleic acid driven LLPS.
Main Methods:
- A model LLPS system using anionic nucleic acids and cationic oligolysine peptides with varied non-ionic amino acids.
- Turbidimetric titrations and microscopic observations to determine critical peptide concentrations (C_crit) for LLPS.
- Correlation analysis between C_crit values and amino acid properties.
Main Results:
- Eight non-ionic amino acids were found to inhibit LLPS, with inhibition correlating positively with hydrophobicity.
- Three aromatic amino acids unexpectedly promoted LLPS, deviating from the hydrophobicity trend.
- This promotion by aromatic amino acids was attributed to interactions with DNA nucleobases.
Conclusions:
- A method to quantify the contribution of non-ionic amino acids to LLPS propensity was established.
- The findings highlight specific amino acid roles in LLPS, particularly the promoting effect of aromatic residues via DNA interactions.
- This work aids in more accurate prediction and description of LLPS in peptides and proteins.
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