Site-Specific Radical Directed Dissociation of Peptides at Phosphorylated Residues

摘要

Phosphorylation plays a critical role in biochemical signaling pathways and is the most common post-translational modification (PTM) of the side chains of proteins. Identification of sites of phosphorylation is essential. The most straightforward (although previously unrealized) approach to obtain this information is to selectively fragment proteins or peptides that are phosphorylated at the site of the modification, revealing both the presence and location of the PTM. Unfortunately, directed fragmentation of specific bonds in large molecules is a difficult task. We have recently reported that site specific radicals generated on tyrosine residues lead to highly localized fragmentations in experiments with whole proteins.