PILIN C-TERMINAL PEPTIDE BINDS ASIALO-GM(1) IN LIPOSOMES - A H-2-NMR STUDY

Wideline H-2-NMR observations are described demonstrating the interact ion of a synthetic peptide (PAK), representing residues 128-144 of the binding domain of pilin surface protein from Pseudomonas aeruginosa, with a complex glycosphingolipid thought to be its natural receptor. T he receptor glycolipid (asialo-GM(1)) carried H-2 probe nuclei on the terminal and next-to-terminal carbohydrate residues and was present as a minor component in fluid phosphatidylcholine liposomes. The peptide induced spectral changes that could be understood as arising from rec eptor motional changes, without receptor immobilization on the NMR tim e scale of 10(4) s(-1). Spectral effects were reversed by reduction of the single peptide disulfide bond- a structural feature previously sh own to be a determinant of PAK conformation (Campbell AP, McInnes C, H odges RS, Sykes BD. 1995. Biochemistry 34:16255-16268). This is the fi rst demonstration of PAK interaction with its epithelial cell receptor in liposomes.