Understanding proteomic diversity at the molecular level is essential for advances in biology and medicine, but sequencing proteins in their full, native form remains challenging. A study in Nature by Motone et al. introduces a nanopore sequencing method that can read single, full-length protein molecules, enabling the detection of single amino acid substitutions and post-translational modifications (PTMs).
The method involves a two-step process. First, a protein is loaded into a nanopore formed by the bacterial lipoprotein CsgC by electrophoretic force, facilitated by a negatively charged tail domain and the addition of a ‘stopper’ sequence. Then, ClpX unfoldase steadily pulls it back through in a trans-to-cis direction. Using synthetic proteins, the authors show their method can detect single amino acid substitutions and can map the activity of kinases, identifying site-specific PTMs such as phosphorylation.
