Nanopores as versatile single-molecule tools: From DNA turbines to protein sequencing.

Abstract

Nanopores offer ample opportunities for studying single biomolecules. I will present some recent examples of nanopore research from my lab: (1) DNA origami turbines powered by nanoscale flow. We demonstrated driven rotary motion of a nanoscale DNA origami turbine which harnesses energy from a water/ion flow generated by a static chemical or electrical potential gradient in a solid-state nanopore. Sustained unidirectional rotary motion of up to 20 revolutions/s were observed. These artificial nano-engines operate autonomously in physiological conditions, converting energy into useful mechanical work. (2) Nanopore-based sequential reading of peptides. We demonstrated a nanopore-based single-molecule peptide reader capable of reliably detecting single amino-acid substitutions within individual peptides. A peptide is linked to a DNA molecule and sequentially pulled through a biological nanopore by a DNA helicase in single amino-acid steps. Stepping ion-current signals enable discrimination of single-amino-acid substitutions in single reads. Notably, we demonstrated the capability to ‘rewind’ peptide reads, obtaining indefinitely many independent reads of the same molecule, yielding an undetectably low read errors. Recently, we expanded this concept to discriminating single post-translational modifications within peptides of mixed charge. These proof-of-concept experiments constitute a promising basis for the development of a single-molecule protein sequencer.