Identification of Two Novel Modifications at Tryptophan Residues

Abstract

Protein post-translational modifications (PTMs) play important roles in cellular physiology. Mass spectrometry (MS) has been developed into a powerful tool to identify all possible protein modifications. Herein, we describe our efforts to deduce the structures of two unknown modifications at tryptophan (Trp) residues (W + 92 Da and W + 108 Da). The two modifications were further confirmed by aligning the MS/MS fragmentation of synthetic peptide with in-vivo peptide identified. Finally, the mimic experiment elucidated how two Trp modifications occur. This study, therefore, expands current knowledge of Trp modifications.

Identification of hydroxylation at aromatic amino acid residues in yeast kinase using mass spectrometry with affinity enrichment

“…Peptides bearing hydroxylation were synthesized by GL Biochem (Shanghai, China). Expression, purification and digestion of protein kinases were carried out as described …”

“…Mass spectrometry has become a fundamental tool for characterization of proteins in biological systems . Tandem mass spectrometry (MS/MS) analysis combined with sequence alignment algorithms enables the identification of all possible protein modifications . Herein, we developed a combined approach to identify hydroxylation at aromatic amino acid residues in protein kinases.…”