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

RATIONALE: Protein kinases represent the key elements in phosphorylation-based signal transmission. Recent studies suggest that hydroxylation may mediate activities of protein kinases. This paper aims to examine the hydroxylation in protein kinases for improving our understanding of the protein modification. METHODS: We combined affinity-based protein purification with MS analysis for identification of novel hydroxylation at aromatic amino acid residues in yeast kinases. RESULTS: We identified 17 hydroxylation at aromatic amino acid residues (10 at Phe, 1 at Tyr and 6 at Trp) using MS analysis. We further characterized the localization and studied the potential significance of these modifications. CONCLUSIONS: This is a new report on the identification of hydroxylation at aromatic amino acid residues in yeast kinases. This study expands the catalog of hydroxylation in kinases and suggests the potential function of hydroxylation. Copyright (C) 2016 John Wiley & Sons, Ltd.