Fig. 4. Identification of amino acids with PTMs and the unnatural amino acid.
a–c, Chemical structure of the amino acids, from left to right: S, P-S (a), K, Ac-K (b), C and CMC (c). d–f, Representative current trace of events generated by simultaneous sensing of proteinogenic amino acids and their PTMs, or of the unnatural amino acid. Final concentrations of S and P-S were both 30 μM (d); of K and Ac-K were 200 μM and 100 μM, respectively (e); and of C and CMC were 3 μM and 20 μM, respectively (f). g–i, Blockade versus dwell time of events from the sensing of individual amino acids and the mixtures.