A novel peptide designed for sensitization of terbium (III) luminescence.
Several synthetic peptides, modelled from a Ca(2+)-binding loop of the EF-hand family of proteins, were prepared containing cysteine residues. The peptide, GDKNADGFICFEEL, was labelled covalently at the cysteine residue (loop position 9) with iodoacetamidosalicylic acid. This novel conjugate is a metal-binding loop containing a salicylic acid side chain that could not only chelate Tb3+ in conjunction with the other chelating groups in the sequence, but could also sensitize Tb3+ luminescence. The loop had a high Tb3+ affinity, with stoichiometric binding observed under experimental conditions. The luminescence from the Tb(3+)-peptide complex was more than 10-fold greater than the luminescence reported from a related peptide which contained Trp as the Tb3+ donor at loop position 7. This peptide has significant potential for use in lanthanide-based time-resolved luminescence immunoassays.
Clark
I D
ID
Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ont.
Hill
I
I
Sikorska-Walker
M
M
MacManus
J P
JP
Szabo
A G
AG
D000595:Amino Acid Sequence; D002135:Calcium-Binding Proteins / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D007460:Iodoacetamide / Q000031:analogs & derivatives; D049449:Luminescence; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D012459:Salicylates; D013725:Terbium / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D010446:Peptide Fragments; D012459:Salicylates; D013725:Terbium; D007460:Iodoacetamide