Yu, Jae-Seok Hong, Seong Cheol Wu, Sangwook Kim, Hyun-Mi Lee, Cheolju Lee, Jun-Seok Lee, Ji Eun Kim, Ki-Bum 2024-01-19T20:34:37Z 2024-01-19T20:34:37Z 2021-09-02 2019-02-07 2040-3364 https://pubs.kist.re.kr/handle/201004/120358 Determination of the amino acid sequence of a protein is critical for understanding various biological processes. Mass spectrometry has mainly been used for protein identification; however, there are limitations to its sensitivity when detecting low abundance proteins. In this study, we attempted to distinguish between three similar peptide sequences (approximate to 40 amino acids, approximate to 5 kDa) that differed only by the location or number of cysteine residues with solid-state nanopores. The cysteine residues are located at one end, one at the center, and at both ends for each of the three peptides. We found that differentiation of the three types of peptides by nanopore signals was difficult. However, when the cysteine residue was labeled with a negatively charged molecule, Flamma (R) 496, the labeled peptides showed distinct signals for each peptide. Comparing the relative current blockades of labeled peptides with applied voltages, we found that the label was able to change peptide conformations and the resulting ionic current signals from the three labeled peptides were distinguished based on the relative current blockade, full width at half-maximum of the current blockade distribution, and single-molecule level peak shape analysis. Our results suggest that solid-state nanopores combined with a targeted labeling strategy could be used to obtain characteristic peptide signatures that could ultimately be used for protein identification. English ROYAL SOC CHEMISTRY PROTEIN TRANSLOCATION SINGLE PROTEIN DNA TRANSPORT RESOLUTION DYNAMICS SIZE Differentiation of selectively labeled peptides using solid-state nanopores Article 10.1039/c8nr09315f 1 NANOSCALE, v.11, no.5, pp.2510 - 2520 NANOSCALE 11 5 2510 2520 scie scopus 000459578800044 2-s2.0-85060939745 Chemistry, Multidisciplinary Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Chemistry Science & Technology - Other Topics Materials Science Physics Article PROTEIN TRANSLOCATION SINGLE PROTEIN DNA TRANSPORT RESOLUTION DYNAMICS SIZE