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.