Translocation of polyampholytes and intrinsically disordered proteins^⋆

Area of Science:

• Polymer Physics
• Biophysics
• Statistical Mechanics

Background:

• Polyampholytes are polymers with both positive and negative charges.
• Intrinsically disordered proteins (IDPs) can mimic polyampholytes in denatured states.
• Understanding polymer and protein translocation through nanopores is crucial for various applications.

Purpose of the Study:

• To investigate the electric-field-driven translocation of synthetic polyampholytes and IDPs through a pore.
• To analyze the impact of charge sequence disorder on synthetic polyampholytes.
• To examine how the engaged end affects translocation and rejection rates of IDPs.

Main Methods:

• Theoretical modeling and simulation of polymer translocation.
• Analysis of translocation dynamics, including speed, rejection time, and blockade time distributions.
• Comparison between synthetic polyampholytes with random charges and IDPs with defined sequences.

Main Results:

• Charge sequence disorder in synthetic polyampholytes significantly slows down translocation dynamics.
• For IDPs, translocation versus rejection rates are dependent on which terminus enters the pore first.
• Translocation speed and blockade time distributions vary for different IDP lengths and structures.

Conclusions:

• Disordered charge sequences in synthetic polyampholytes impede efficient pore translocation.
• The specific end of an IDP engaging with the pore dictates its translocation outcome.
• IDP translocation is sensitive to sequence length and structural properties, offering insights into biological transport mechanisms.