Lysine formylation is a newly discovered post-translational modification (PTM) in histones and other nuclear proteins; it has a well-recognized but poorly defined role in chromatin conformation modulation and gene expression. To date, there is no general method to site-specifically incorporate N(ε)-formyllysine at a defined site of a protein. Here we report the highly efficient genetic incorporation of the unnatural amino acid N(ε)-formyllysine into proteins produced in Escherichia coli and mammalian cells, by using an orthogonal N(ε)-formyllysine tRNAsynthetase/tRNACUA pair. This technique can be applied to study the role of lysine formylation in epigenetic regulation.
Keywords: amino acids; formyllysine; gene technology; histones; post-translational modifications.
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