In this project, we investigated whether diverse spirochete species contain lysinoalanine cross-linkages between conserved residues in their flagellar hook proteins (FlgE). We examined the following species: Treponema denticola¸ Borreliella burgdorferi, Treponema phagedenis, Treponema pallidum, Brachyspira hyodysenteriae, Leptospira interrogans. For each bacterial species, we examined a variety of different sample types, including recombinantly produced FlgE, polyhooks purified from flik knock-out strains, and wild-type periplasmic filaments. Overall, our data suggests that lysinoalanine crosslinking in a conserved FlgE post-translational modification in spirochetes and is required for the unique motility of these organisms. For more information, please see the following manuscript: https://doi.org/10.1101/2023.06.13.544825.