Figure 1.
Overview of negatively stained N. gonorrhoeae membranes.
(A) Membranes isolated from strain MS11. (B) Membranes isolated from a pilQ deletion mutant strain. (C) Immungold labeling of membranes from strain MS11 with PilQ antibody. The scale bar is 1000 Å.
Figure 2.
Secretin structures observed by negative stain imaging of whole cells.
(A) Piliated and (B) non-piliated cells of N. gonorrhoeae strain were imaged by electron microscopy. The scale bar is 1000 Å.
Figure 3.
Class averages of single particle electron microscopy images of the PilQ complex from N. gonorrhoeae.
(A) wild-type projection map (B) with 7-fold symmetry imposed on the peripheral spikes (C) with 7-fold symmetry imposed using the class average of (B) as template (D) class average of the central ring, after masking out the second ring and spikes (E) central ring 2D map with positions of densities indicated (F) central ring 2D map with imposed 14-fold symmetry. The projection map of the PilQ complex in frame A has a resolution of 20 Å. The scale bar is 100 Å.
Figure 4.
Electron microscopy analysis of the PilQ complexes in isolated membranes.
(A) N. meningitidis membranes negatively stained with 2% uranyl acetate. (B–D) Average of 8,000 projections of the PilQ complexes from N. meningitidis showing classes with single, double and incomplete rings, respectively. (E) Average of 10,000 projections of PilQ complex from N. gonorrhoeae showing central and the peripheral ring having 14-fold symmetry. (F-J) To investigate the number of copies of the peripheral ring, 17- to 21-fold rotational symmetry (white numbering) was imposed on the classes after completion of the analysis. The strongest rotational symmetry within the second ring is in frame H. The scale bar for frame (A) is 1000 Å, and equals 100 Å for frame (B–J).
Figure 5.
Single particle analysis of particles derived from membranes of different N. gonorrhoeae deletion mutant strains.
Projection maps derived from membranes isolated from (A) N. gonorrhoeae strain MS11, (B) with 7-fold symmetry imposed, (C) the pilC1/C2 deletion mutant, (D) the pilC1/C2 deletion mutant with 7-fold symmetry imposed, (E) the pilP deletion mutant, (F) the pilP deletion mutant with 19-fold symmetry imposed, (G) the pilF deletion mutant, (H) the pilF deletion mutant with 7-fold symmetry imposed, (I) the the pilE deletion mutant, (J) the pilE deletion mutant with 19-fold symmetry imposed, (K) the pilW deletion mutant, and (L) the pilW deletion mutant with 7-fold symmetry imposed, Scale bar equals 100 Å.
Table 1.
Strains used in this study.
Table 2.
Primers used in this study.