Figure 4.
Processing of the membrane protein YfnI by the type I signal peptidases SipT and SipV. Single and multiple signal peptidase (sip) mutants of B. subtilis were grown in L-broth, and proteins in the growth medium were harvested 1 h after entry into the stationary phase. After precipitation with TCA, the extracellular proteins were separated by 2D PAGE as described in the Methods section. The three spots that correspond to the YfnI protein are encircled.
