Abstract
Polymeric flagellin consists of four linearly connected domains labeled D0, D1, D2, and D3, which are arranged from the inside to the outside of the filament. The disordered terminal regions are involved in D0 and partly in D1, forming long helical bundles, and their direct interaction is responsible for stabilizing the filament structure.A central segment from Tyr 190 to Val 283 makes up domain D3, which is exposed on the surface of flagellar filaments. D3 is a structurally independent part of flagellin; it is not essential for filament formation