Enzyme-less nanopore detection of post-translational modifications within long polypeptides

Means to sequence DNA and RNA quickly and cheaply have revolutionized biology and medicine. The ability to analyse cellular proteins and their millions of variants would be an advance of comparable importance, but requires a fresh technical approach. We use electroosmosis for the non-enzymatic capture, unfolding and translocation of individual polypeptides of more than 1200 residues by a protein nanopore. By monitoring the ionic current carried by the nanopore, we locate post-translational modifications deep within the polypeptide chains, and thereby lay the groundwork for obtaining inventories of the proteoforms in cells and tissues. ### Competing Interest Statement H.B. is the founder of, a consultant for, and a shareholder of Oxford Nanopore Technologies, a company engaged in the development of nanopore sensing and sequencing technologies. P.M.B., W.-H.L., Y.Q., M.R.R., H.B., and S.G.-M., have filed patents describing the electroosmotically active nanopores and their applications of proteoform characterisation.