FIG. 3.

(A) FPLC fractionation of 100,000 × g supernatant fraction of concentrated RB1057 culture supernatant (10,000 × g) with a 0.05 to 0.2 M NaCl gradient in 0.02 M Tris buffer (pH 7.5). (B) FPLC fractions from a concentrate of the RB1057 inhibitor run on a sodium dodecyl sulfate–10% polyacrylamide gel electrophoresis gel and stained with Coomassie blue (19). Molecular mass standards (in kilodaltons, shown at left) are in the leftmost lane. Well assay titers are the reciprocals of the dilutions giving the effective concentrations.