Figure 1.

Structure of the flagellar organelle of Campylobacter jejuni and Helicobacter pylori. The major components common to the flagella of C. jejuni and H. pylori are shown. Other relatively less-characterized proteins specific to each bacterium are not shown for simplicity. Flagellar components are color-coded based on the classification of the respective genes in the transcriptional regulatory cascade for the organisms: red (class 1), blue (class 2), and green (class 3). An exception includes flaB, which is a σ⁵⁴-dependent class 2 gene. Proteins in gray include those encoded by genes whose transcription has not been analyzed or is known to be outside the flagellar transcriptional hierarchy. Other class 1 proteins that are required for expression of σ⁵⁴-dependent class 2 genes but are not part of the flagellar structure are not shown. Abbreviation: T3SS, type III secretion system.