Fig 3.

Protein purification and comparative proteomics yield candidate antimicrobial proteins. (A) Biochemical purification scheme used to generate candidate antimicrobial proteins. Three biological replicates were submitted for proteomics analysis. (B) Representative results from the final protein purification step (size exclusion chromatography). One biological replicate is shown. Active fractions, marked in red, are tracked via chromatogram (i), agar diffusion assay against S. epidermidis (ii), and SDS-PAGE (iii, 9 µL from each sample). Chromatography product from active fractions (A4 and A5) along with neighboring inactive fractions (A3 and A6) was submitted for proteomics analysis. (C) Representative results across all sequential protein purification steps (molecular weight fractionation, ion exchange chromatography, and size exclusion chromatography). One biological replicate is shown. SDS-PAGE (top, 30 µL from each sample), agar diffusion assay against USA300 MRSA (middle), and total protein concentration via NanoDrop A280 (bottom) are tracked for pooled active fractions from each purification step.