Single-Molecule Protein Identification by Sub-Nanopore Sensors
This work addresses protein identification for applications such as proteomics, but it is incremental as it builds on existing nanopore technology.
The authors tackled the challenge of single-molecule protein identification by exploring sub-nanopore sensors, developing an algorithm to analyze electrical current blockade signals, and found that current technology can match nanospectra against small protein databases like bacterial proteomes.
Recent advances in top-down mass spectrometry enabled identification of intact proteins, but this technology still faces challenges. For example, top-down mass spectrometry suffers from a lack of sensitivity since the ion counts for a single fragmentation event are often low. In contrast, nanopore technology is exquisitely sensitive to single intact molecules, but it has only been successfully applied to DNA sequencing, so far. Here, we explore the potential of sub-nanopores for single-molecule protein identification (SMPI) and describe an algorithm for identification of the electrical current blockade signal (nanospectrum) resulting from the translocation of a denaturated, linearly charged protein through a sub-nanopore. The analysis of identification p-values suggests that the current technology is already sufficient for matching nanospectra against small protein databases, e.g., protein identification in bacterial proteomes.