Unclogged pores: designer channels for protein translocation

Abstract

Nanopores have the potential to revolutionize the field of protein sequencing, but due to the biochemical complexity of polypeptide sequences, they have remained mostly theoretical. In recent work, Sauciuc et al. engineer the protein nanopore CytK to produce an electroosmotic force capable of translocating unfolded polypeptides regardless of their charge distributions, an important step toward single-file protein nanopore sequencing.

Fig. 1. The modified CytK pore drives translocation of unfolded polypeptides; this translocation can be measured as a change in current.

a The negative charges of the 2E-4D modified CytK (cyan) create a strong EOF capable of translocating any linear, unfolded polypeptide (dark blue), even when the EPF has an opposite direction. Myoglobin is shown here as an example (PDB ID 1MBN) shown as an example, rendered in Pymol. b The passage of a linear polypeptide can be measured by changes in the current across the pore; an example trace is shown here with the polypeptide translocating during the trace peak (τ).