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. 2019 Feb 1;14(2):e0211632. doi: 10.1371/journal.pone.0211632

Fig 2. Neutrophil elastase degrades a 90kDa Spn CW protein in vitro.

Fig 2

CW was isolated from TIGR4 and ΔpepN cells of S. pneumoniae and were left untreated or incubated with 68μM NE or 10μM CG. (A) Samples were analyzed using an AnykD gradient Tris-glycine polyacrylamide gel followed by colloidal Coomassie blue staining. Arrow heads indicate bands degraded by NE. Black arrow heads highlight the 90kDa species degraded by NE. (B) The intensity of the 90 kDa band in the untreated control or in CW samples treated with NE was quantified using ImageStudioLite. The data are presented as relative band intensity normalized to a blank lane. Data shown are means ± SD from 5 independent experiments. P = 0.019 using a Student’s t-test. (C) To determine the identity of the 90kDa protein that is degraded by NE, we excised this band from both the untreated and NE-treated lanes and had it analyzed via mass spectrometry. Additionally, this analysis quantified the relative abundance of the 90kDa protein in both the untreated and NE-treated samples. The gel is from one experiment representative of 5 independent experiments. The mass spectrometry analysis is from 2 of those independent experiments. NE, neutrophil elastase; CG, cathepsin G.