Histogram from Scientific Research

Sizing of low-molecular weight oligomers formed by the protein human serum albumin (HSA). Shown is a burst intensity histogram, which displays all bursts extracted from a single smMDS step scan measurement of HSA (10 pM). Intensities are normalized intensities with respect to burst duration. Four regions (blue, orange, green, and red), which correspond to HSA monomer and HSA dimer, trimer, and tetramer, are defined in the burst intensity histogram. These were obtained by fitting the distribution with a skew-normal distribution function for monomeric HSA and three Gaussian functions for dimeric, trimeric, and tetrameric HSA (see main text for details). The center positions for the oligomers (dimer: 150.66 photons/ms, trimer: 225.99 photons/ms, and tetramer: 301.32 photons/ms) are multiples of the normalized intensity of the monomer (I monomer = 75.33 photons/ms). The widths of the regions reflect one standard deviation of the distribution of monomeric HSA (σ monomer = 37.44 photons/ms).

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