Biology subjects

Sauciuc, A.

Publications and source records attributed to Sauciuc, A..

2 recordsLinked to original sources

bioRxiv2024

Unravelled proteins form blobs during translocation across nanopores

The electroosmotic-driven transport of unravelled proteins across nanopores is an important biological process that is now under investigation for the rapid analysis and sequencing of proteins. For this approach to work, however, it is crucial that the polymer is threaded in single file. Here we found that, contrary to the electrophoretic transport of charged polymers such as DNA, during polypeptide translocation blob-like structures typically form inside nanopores. Comparisons between different nanopore sizes, shapes and surface chemistries showed that under electroosmotic-dominated regimes single-file transport of polypeptides can be achieved using nanopores that simultaneously have an entry and an internal diameter that is smaller than the persistence length of the polymer, have a uniform non-sticky (i.e. non-aromatic) nanopore inner surface, and using moderate translocation velocities.

biophysics↗

bioRxiv2023

An engineered electroosmotic flow transports unravelled proteins across nanopores

The development of a technology capable of sequencing single proteins holds promise to unravel new biological information hidden in ensemble analysis. However, new techniques must be first developed. In one approach, proteins are unfolded and translocate across a nanopore under an external bias. Unlike DNA, however, proteins do not have a uniform charge, and the electrophoretic force cannot be used to translocate proteins. Here, we show that by introducing sets of charges spaced by ~1 nm an otherwise neutral nanopore an electroosmotic force is created that induces the unidirectional transport of polypeptides, even against relatively strong electrophoretic forces. Unstructured polypeptides and native proteins unfolded with urea produce current signatures as they traversed the nanopore, which could lead to quick protein identifcation. This approach can be used to translocate and stretch proteins in non-enzymatic protein identification and enzymatic protein sequencing approaches.

biophysics↗