FIG. 2.

SDS-PAGE and immunoblot staining showing lack of human FN cleavage by the 28-kDa His340Ala mutant made by E. coli. Lanes: 1, molecular mass standards of the sizes indicated at the left; 2, FN without incubation; 3, FN incubated without streptococcal mutant enzyme; 4, FN incubated with His340Ala mutant protein; 5, FN incubated with Cys192Ser mutant protein (control); 6, FN incubated with 28-kDa wild-type streptococcal cysteine protease purified from strain MGAS 1719.