FIG 1.

Individual Cag T4SS ATPases are not required for assembly of the Cag T4SS core complex. H. pylori mutant strains lacking genes encoding individual ATPases (Δcagα, Δcagβ, and ΔcagE) were modified by introducing a gene encoding HA-CagF into the ureAB chromosomal locus, resulting in strains with the genotypes indicated in the figure (corresponding to FC1.1 [Δcagα/HA-CagF], FC2.1 [Δcagβ/HA-CagF], and FC3.1 [cagE::kan/HA-CagF] in Table 1). T4SS core complexes were immunopurified from these strains, and the preparations were analyzed and visualized by negative-stain electron microscopy (magnification, ×28,000). (A) Core complexes purified from a wild-type (WT) strain engineered to produce HA-CagF (WT/HA-CagF) (positive control). (B to D) Core complexes isolated from mutant strains engineered to produce HA-CagF (Δcagα/HA-CagF, Δcagβ/HA-CagF, and cagE::kan/HA-CagF). Scale bars, 25 nm.