FIG. 4.

Effects of VirB9.i2 mutations on exocellular and cellular forms of VirB2 pilin. (A) Exocellular VirB2 as a marker for the T pilus detected in material recovered by mechanical shearing of equivalent numbers of AS-induced cells. (B) Cellular form of VirB2 in the corresponding shear-resistant fraction. Protein samples were subjected to SDS-PAGE and development of immunoblots with anti-VirB2 antibodies. WT, strain A348; ΔB9, strains PC1009 and PC1009 producing native VirB9 (B9) and the VirB9.i2 mutant proteins.