'Flagella-driven motility is essential for the entry of H. pylori into the mucus layer and for maintaining a swimming reservoir in the mucus (Fig. 3). H. pylori has a unipolar bundle of rotating sheathed flagella, with filaments composed of two flagellin proteins that evade activating the innate immune system via TLR5 due to specific adaptation of their amino acid sequences'
From Andersen-Nissen et al, PNAS 2005.
"We map the site responsible for TLR5 evasion to amino acids 89-96 of the N-terminal D1 domain, which is centrally positioned within the previously defined TLR5 recognition site. Salmonella flagellin is strongly recognized by TLR5, but mutating residues 89-96 to the corresponding H. pylori flaA sequence abolishes TLR5 recognition and also destroys bacterial motility."
https://www.pnas.org/doi/full/10.1073/pnas.0502040102