Subcellular localization of K99 fimbrial subunits and effect of temperature on subunit synthesis and assembly.

Analysis of the biogenesis of K99 fimbriae indicated that the fimbrial subunits were synthesized at the cytoplasmic membrane and accumulated in the periplasm before they appeared at the cell surface. Cells grown at 18 degrees C contained a small pool of fimbrial subunits. After a shift to 37 degrees C, the cells required about 1 h before they were able to synthesize fimbriae, concomitant with a dramatic increase in K99 concentration.