Zymogram activity gel. HF-treated peptidoglycan from S. mutans UA159 was incorporated into a 7.5% SDS-polyacrylamide gel. Nondenatured surface proteins were separated on the gel. Lane 1, UA159; lane 2, UA159D65::fPcEm; lane 3, NG8; lane 4, SrtA−; lane 5, PC3370; lane 6, OMZ175; lane M, prestained molecular mass markers (kilodaltons). The asterisk indicates the band associated with SmaA.