On-bead chemical synthesis and display of phosphopeptides for affinity pull-down proteomics

Chembiochem. 2006 Apr;7(4):623-30. doi: 10.1002/cbic.200500378.

Abstract

We describe a new method for phosphopeptide proteomics based on the solid-phase synthesis of phosphopeptides on beads suitable for affinity pull-down experiments. Peptide sequences containing the Bad Ser112 and Ser136 phosphorylation motifs were used as bait in affinity pull-down experiments to determine their ability to bind 14-3-3 proteins. Support-bound peptides were assembled directly on the solid support (PEGA) by standard solid-phase synthesis through a BAL-type handle. The peptides were varied in length and sequence. This synthetic strategy also allowed introduction of a soft electrophile (aldehyde) at the C terminus for potential activity-based proteomics. The synthetic support-bound Bad phosphopeptides were able to pull down 14-3-3zeta. Furthermore, Bad phosphopeptides bound endogenous 14-3-3 proteins, and all seven members of the 14-3-3 family were identified by mass spectrometry. In control experiments, none of the unphosphorylated Bad peptides bound transfected 14-3-3zeta or endogenous 14-3-3. We conclude that the combined synthesis and display of phosphopeptides on-bead is a fast and efficient method for affinity pull-down proteomics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Molecular Structure
  • Phosphopeptides / chemical synthesis*
  • Phosphopeptides / chemistry
  • Proteomics*

Substances

  • Phosphopeptides