HETEROBINARY ADHESINS BASED ON THE ESCHERICHIA-COLI FIMH FIMBRIAL PROTEIN

The FimH adhesin of Escherichia coli type 1 fimbriae confers the abili ty to bind to D-mannosides by virtue of a receptor-binding domain loca ted in its N-terminal region. This protein was engineered into a heter obifunctional adhesin by introducing a secondary binding site in the C -terminal region, The insertion of histidine clusters into this site r esulted in coordination of various metal ions by recombinant cells exp ressing chimeric FimH proteins. In addition, libraries consisting of r andom peptide sequences inserted into the FimH display system and scre ened by a ''panning'' technique were used to identify specific sequenc es conferring the ability to adhere to Ni2+ and Cu2+. Recombinant cell s expressing heterobifunctional FimH adhesins could adhere simultaneou sly to both metals and saccharides. Finally, combining the metal-bindi ng modifications with alterations in the natural receptor-binding regi on demonstrated the ability to independently modulate the binding of F imH to two ligands simultaneously.