FIG. 1.

Incorporation of pilin subunits into pili in the absence of individual subunits. Bacterial and culture fractions (cell wall [cw], protoplast [pplast], and culture supernatant [sup]) of the wild type (wt) and an rrgA, rrgB, or rrgC mutant strain were separated by SDS-polyacrylamide gel electrophoresis, transferred to nitrocellulose, and probed with antisera against RrgB (A), RrgA (B), and RrgC (C). As a negative control, the cell wall fraction of a mutant strain corresponding to the antiserum that was used in each panel is included. The HMW bands represent pili of differing lengths. The values on the left of each panel are molecular weight marker sizes in kilodaltons.