Nanopore 'Chop and Measure' Method Achieves Single-Amino-Acid Peptide Sequencing

Researchers have unveiled a groundbreaking nanopore-based methodology capable of sequencing peptides with single-amino-acid resolution, a significant advancement detailed in a study published online in the prestigious journal *Nature* on July 29, 2026. This innovative technique, dubbed 'chop and measure,' employs a cyclical process of enzymatic digestion and precise N-terminus re-reading to progressively shorten a peptide, one amino acid at a time. The study's digital object identifier is 10.1038/s41586-026-10881-1.

The core principle of this method involves immobilizing a target peptide within a nanopore. Subsequently, a specific enzyme is introduced to cleave off a single amino acid from the N-terminal end of the immobilized peptide. Following this enzymatic digestion, the nanopore system meticulously reads the remaining peptide sequence. This cycle of enzymatic shortening and subsequent nanopore reading is then repeated sequentially. By carefully analyzing the changes in the nanopore signal after each cleavage event, scientists can accurately deduce the identity of the removed amino acid. This iterative process allows for the reconstruction of the entire peptide sequence with unprecedented accuracy at the single-amino-acid level.

This breakthrough holds substantial implications across various scientific disciplines, including proteomics, drug discovery, and diagnostics. Traditional peptide sequencing methods, such as Edman degradation or mass spectrometry-based approaches, often encounter limitations in achieving definitive single-amino-acid resolution, particularly for longer or more complex peptide chains. The nanopore approach, by dissecting the sequencing process into discrete, quantifiable steps, effectively circumvents these challenges. The ability to precisely identify each amino acid in a peptide chain is fundamental for understanding protein function, identifying critical post-translational modifications (PTMs) that influence protein activity, and developing highly targeted therapeutic agents.

The researchers validated their method, demonstrating its capability to reliably distinguish between adjacent amino acids, a crucial prerequisite for high-resolution sequencing. The repetitive reading of the N-terminus after each digestion step provides redundant data, significantly enhancing the robustness and overall accuracy of the sequence determination. This advancement represents a substantial leap forward in analytical chemistry and molecular biology, offering a powerful new tool for researchers investigating the intricate world of peptides and proteins. The development builds upon earlier work in nanopore sequencing, which has previously shown promise for DNA and RNA analysis, adapting and refining the technology for the more complex challenge of protein fragments.