Manifold of Polyampholyte Necklaces: From Charge Migration to Hierarchical Structure

Area of Science:

• Polymer Physics
• Biophysics
• Computational Chemistry

Background:

• Polyampholytes are polymers with both positive and negative charges.
• Their conformations are influenced by electrostatic and non-electrostatic interactions.
• Previous models did not fully capture the complexity of charge-imbalanced systems.

Purpose of the Study:

• To comprehensively map the conformational states of charge-imbalanced polyampholytes.
• To identify and characterize novel conformational regimes.
• To relate polyampholyte behavior to intrinsically disordered proteins.

Main Methods:

• Theoretical scaling analysis with Markov charge statistics.
• Molecular dynamics simulations.
• Construction of a state diagram based on charge blockiness and solvent quality.

Main Results:

• Identified ten distinct scaling regimes for polyampholyte conformations.
• Classified necklaces into three types: charge-in-beads, charge-in-strings, and novel hierarchical necklaces.
• Hierarchical necklaces exhibit coexisting beads of two sizes under specific conditions.

Conclusions:

• Scaling predictions for polyampholyte conformations are validated by simulations.
• The study provides a detailed phase diagram for these complex polymers.
• Findings offer insights into the structural behavior of intrinsically disordered proteins/regions (IDPs/IDRs).