Flagellin

Flagellins are a family of proteins present in flagellated bacteria[1] which arrange themselves in a hollow cylinder to form the filament in a bacterial flagellum.

While the termini of the protein are quite similar among all bacterial flagellins, the middle portion is wildly variable and can be absent in some species.

Flagellin-like structural proteins are found in other portions of the flagellum, such as the hook (flgE; P75937), the rod at the base, and the cap at the top.

[7] The middle part of  E. coli (and related) flagellin, D3, displays a beta-folium fold and appears to maintain flagellar stability.

[16] Both flagellin and UV-C act similarly to increase homologous recombination, as demonstrated by Molinier et al 2006.

[17] Mitogen-activated-protein-kinases (MAPK) acts as downstream signalling compounds, leading ultimately to PAMP-triggered immunity in which more than 900 genes are up-/down-regulated upon flg22 treatment.