Issue 2, 2021

Designed alpha-helical barrels for charge-selective peptide translocation

Abstract

Synthetic alpha-helix based pores for selective sensing of peptides have not been characterized previously. Here, we report large transmembrane pores, pPorA formed from short synthetic alpha-helical peptides of tunable conductance and selectivity for single-molecule sensing of peptides. We quantified the selective translocation kinetics of differently charged cationic and anionic peptides through these synthetic pores at single-molecule resolution. The charged peptides are electrophoretically pulled into the pores resulting in an increase in the dissociation rate with the voltage indicating successful translocation of peptides. More specifically, we elucidated the charge pattern lining the pore lumen and the orientation of the pores in the membrane based on the asymmetry in the peptide-binding kinetics. The salt and pH-dependent measurements confirm the electrostatic dominance and charge selectivity in controlling target peptide interaction with the pores. Remarkably, we tuned the selectivity of the pores to charged peptides by modifying the charge composition of the pores, thus establishing the molecular and electrostatic basis of peptide translocation. We suggest that these synthetic pores that selectively conduct specific ions and biomolecules are advantageous for nanopore proteomics analysis and synthetic nanobiotechnology applications.

Graphical abstract: Designed alpha-helical barrels for charge-selective peptide translocation

Supplementary files

Article information

Article type
Edge Article
Submitted
03 9 2020
Accepted
04 11 2020
First published
04 11 2020
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY-NC license

Chem. Sci., 2021,12, 639-649

Designed alpha-helical barrels for charge-selective peptide translocation

S. K. R., N. Puthumadathil, A. H. Shaji, K. Santhosh Kumar, G. Mohan and K. R. Mahendran, Chem. Sci., 2021, 12, 639 DOI: 10.1039/D0SC04856A

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