Fig. 3 | Nature Communications

Fig. 3

From: Electro-osmotic capture and ionic discrimination of peptide and protein biomarkers with FraC nanopores

Fig. 3

Biomarker characterization with WtFraC at pH 4.5. From top to bottom: surface representation with molecular surface and cartoon representations (PyMOL) of the biomarker, a representative trace obtained under the indicated applied potential, a heatplot depicting the dwell time distribution vs. I res% at the same applied potential, the voltage dependence of I res%, the voltage dependence of the dwell times, and the capture frequency. a Chymotrypsin (25 kD, PDB: 5CHA), b β2-microglobulin (11.6 kD, PDB: 1LDS), c human EGF (6.2 kD, PDB: 1JL9), d endothelin 1 (2.5 kD, PDB: 1EDN), and e angiotensin I (1.3 kD), respectively. Angiotensin I is depicted as a random structure drawn with PyMOL. The concentrations of the biomarkers were: 200 nM for chymotrypsin, 200 nM for β2-microglobulin, 2 µM for human EGF, 1 µM for endothelin 1, and 2 µM for angiotensin I, respectively. Isoelectric points of biomarkers are obtained from literatures or with the online calculation tool PepCalc. Error bars represent the standard deviation obtained from at least 3 repeats and at least 300 events for each repeat. The voltage dependencies of capture frequencies were fitted to quadratic functions. With the exception of EGF, voltage dependencies of dwell times were fitted to single exponentials. All remaining data were fitted using a B-spline function (Origin 8.1). All recordings were collected with 50 kHz sampling rate and 10 kHz low-pass Bessel filter. Detailed numbers and analysis for each data point could be found in the supporting information (Supplementary Figs. 1115 and Supplementary Table 7)

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