FIG. 3.

(A) Modular representation of PilQ. The 29-amino-acid signal sequence (SS), the low-homology region, and the three conserved subdomains are shown. (B) Protein sequence of PilQ. The signal sequence is underlined. The two residues that are changed in PilQ1 are in boldface (residues 741 and 762), as is the signature sequence (V,I)PXL(S,G)XIPXXGXLF. (C) Protein sequence of OrfL. A putative type II signal sequence is underlined, and the signature sequence for a phosphopantetheine attachment site is in boldface.