CAMPERI Silvia Andrea
Identification of protein-binding peptides by direct MALDI-TOF-MS analysis of peptide beads selected from the screening of one-bead-one peptide combinatorial libraries
M. M. MARANI; E. OLIVEIRA; S. CÔTÉ; S. A. CAMPERI; F. ALBERICIO; O. CASCONE
Elsevier Science Lt.
Lugar: Amsterdam; Año: 2007 vol. 370 p. 215 - 215
A fast and inexpensive strategy for the identification of peptide ligands by direct matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis of peptide-beads screened from one-bead-one-peptide combinatorial libraries is herein described. Streptavidin was used as the model protein. A combinatorial library of 6561 peptides was synthesised on ChemMatrixTM resin by the divide-couple-recombine method. 4-hydroxymethylbenzoic acid was used as the linker and five residues of Gly were incorporated at the C-termini to increase the final peptide molecular weight. Positive control peptides with the HPQ motif and negative control peptides without the HPQ motif evidenced that the linker and the five residues of Gly have neither impaired the specific binding nor facilitated unspecific binding. After screening the library, positive beads were isolated and washed with 8 M guanidine hydrochloride. The beads were sliced into two or four pieces, deposited onto the stainless-steel MALDI sample plate and treated with ammonia vapour to release the peptides. 26 beads picked at random from the library were also subjected to the same treatment. All the samples were analysed by MALDI-TOF-MS and the peptides unambiguously identified with very good reproducibility between the bead pieces, thus evidencing the good homogeneity of the bead. All the sequences obtained from the screening contained HPQ.