Bacterial and archaeal flagella as prokaryotic motility organelles

The properties and molecular organization of flagella-the bacterial and archaeal motility organelles-are reviewed. The organization of these functional motility elements of prokaryotic organisms belonging to different kingdoms is compared. A mechanism for both in vivo and in vitro assembly of bacterial flagellum filaments (BFFs) is discussed, and similarity is supposed between flagellin and actin with regard to their polymeric forms (BFF and F-actin). Our own data on intracellular fixation of the Halobacterium salinarium flagellum are presented. Comparative characteristics of intracellular fixation of bacterial and archaeal flagella are also described.