The synthesis of bacterial flagella (the "tails" they use to propel their swimming motion) served as the foundation of one of my most-cited papers:
Plaxco KW & Groß M (1997): Nature 386, 657-659 (17.4.1997)
Cell biology: The importance of being unfolded (News and Views)
where Kevin Plaxco and I proposed that the regulatory protein FlgM, which serves its function in an unfolded state, might just be one of many such "unfolded yet active" proteins. Which turned out to be quite true.
The group of Kelly Hughes, whose work our comment was based on, has now investigated the energy source of the process of building up bacterial flagella, which is quite intriguing as proteins are pumped out through the hollow interior of the growing structure. Surprisingly it's not driven by ATP, but only by a proton gradient.
It's in the current issue of Nature, page 489:
Energy source of flagellar type III secretion
Koushik Paul, Marc Erhardt, Takanori Hirano, David F. Blair & Kelly T. Hughes