M. Hammar et al., NUCLEATOR-DEPENDENT INTERCELLULAR ASSEMBLY OF ADHESIVE CURLI ORGANELLES IN ESCHERICHIA-COLI, Proceedings of the National Academy of Sciences of the United Statesof America, 93(13), 1996, pp. 6562-6566
Bacterial adhesion to other bacteria, to eukaryotic cells, and to extr
acellular matrix proteins is frequently mediated by cell surface-assoc
iated polymers (fimbriae) consisting of one or more subunit proteins.
We have found that polymerization of curlin to fimbriae-like structure
s (curli) on the surface of Escherichia coli markedly differs from the
prevailing model for fimbrial assembly in that it occurs extracellula
rly through a self-assembly process depending on a specific nucleator
protein. The cell surface-bound nucleator primes the polymerization of
curlin secreted by the nucleator-presenting cell or by adjacent cells
. The addition of monomers to the growing filament seems to be driven
by mass action and guided only by the diffusion gradient between the s
ource of secreted monomer and the surface of monomer condensation.