Updated project metadata. In this project we developed phosphopeptides functionalized with methacrylate ester warheads installed on a cysteine residue, which bind covalently to the protein 14-3-3 sigma. We prepared complexes of the purified protein with the peptides and used trypsin digestion and LC-MSMS to elucidate the binding site of the peptides, by comparison of compound-treated complexes to DMSO-treated protein and observing the disappearance on non-modified peptides. The file names are based on internal names used for the project and are distinct from the names given to the peptides in the final publication. Names are as follows: 4IEA - peptide 3 in the final publication 128C - peptide 8 in the final publication 132C - peptide 11 in the final publication