FIG. 3.
Protein purification analysis and turbidity assay with selected B30 endolysin truncated proteins. (A) Representative SDS-PAGE gel containing B30 endolysin and derived proteins purified with nickel affinity columns. Purified proteins were analyzed by standard 15% SDS-PAGE performed with Tris-glycine buffer at 131 V for 1.5 h in a Bio-Rad Mini-PROTEAN 3 gel apparatus according to the manufacturer's instructions. Gels were stained with BioSafe Coomassie blue stain (Bio-Rad) for 1 h and then rinsed in distilled water overnight. Lane M, molecular mass protein standards (Kaleidoscope protein standards; Bio-Rad); lane 1, 1-156; lane 2, 1-182; lane 3, 1-356; lane 4, full-length 1-443 protein. (B) Turbidity assay results with three bacterial strains obtained by using 100 μg of each B30 endolysin-derived protein. Black bars, 1-156; white bars, 1-182; plaid bars, 1-356; striped bars, full-length 1-443. The turbidity data are the results of three independent experiments performed with three unique preparations of purified protein. Specific activity is expressed in OD600/hour/milligram. S. agal., S. agalactiae.