The Caulobacter crescentus flagellar filament is assembled from multiple fl
agellin proteins that are encoded by six genes. The amino acid sequences of
the FljJ and FljL flagellins are divergent from those of the other four fl
agellins. Since these flagellins are the first to be assembled in the flage
llar filament, one or both might have specialized to facilitate the initiat
ion of filament assembly.