FIG. 4.

Two views of a ribbon diagram of PelC with regions required for species-specific secretion shaded. Regions A and C and the C-terminal (C-term) branch of region E, none of which are required for species-specific secretion, are indicated in white. Regions B and D, required for targeting, are lightly shaded. Region E, excluding the C-terminal branch, is shaded darkly because the external loops in this region are considered the best candidates for a primary targeting signal. Disulfide bonds linking C72 to C155 and C329 to 352, where visible, are indicated in black.