Site-Specific Mapping and Time-Resolved Monitoring of Lysine Methylation by High-Resolution NMR Spectroscopy

Methylation and acetylation of protein lysine residues
constitute
abundant post-translational modifications (PTMs) that regulate a plethora
of biological processes. In eukaryotic proteins, lysines are often
mono-, di-, or trimethylated, which may signal different biological
outcomes. Deconvoluting these different PTM types and PTM states is
not easily accomplished with existing analytical tools. Here, we demonstrate
the unique ability of NMR spectroscopy to discriminate between lysine
acetylation and mono-, di-, or trimethylation in a site-specific and
quantitative manner. This enables mapping and monitoring of lysine
acetylation and methylation reactions in a nondisruptive and continuous
fashion. Time-resolved NMR measurements of different methylation events
in complex environments including cell extracts contribute to our
understanding of how these PTMs are established in vitro and in vivo.