FIG. 7.

Mapping of trypsin cleavage sites with the HA epitope tags. Iron-stressed gonococci were incubated with trypsin for 0, 10, 20, or 30 min before the protease was inactivated by the addition of aprotinin. The trypsinized cells were pelleted, lysed, and separated by SDS-PAGE. After transfer, the blots were probed with a monoclonal anti-HA antibody conjugated to peroxidase. The length of the trypsin incubation (in minutes) is shown above each lane; lanes labeled NT contain proteins that were not treated with trypsin before the addition of aprotinin. The approximate positions of molecular mass markers (MW), in kilodaltons, are located to the left of the blots. The previously characterized TbpA-derived trypsin digestion products, T1 (95.2 kDa) and T2 (54.9 kDa), are labeled on the right.