An increasing number of post-translational modifications (PTMs) have been gradually discovered on both cytoplasmic and nucleic proteins, due to the development of mass spectrum and tandem MS (MS/MS) techniques. Although they are generally reported to be important to the nucleosome structure, gene function, and enzymatic regulation, the detailed mechanisms and signaling pathways remain elusive. A primary question is to get sufficient amount of protein of interests (POIs) with PTMs at specific sites. Methylation is one of the most widely existing lysine modifications, and can occur as mono-, di-, and tri-methylations. Similar to other PTMs, histone methylation can influence the structure and functions of chromatin in eukaryotic cells, and recruit many different binding proteins for transcription regulation. As an important epigenetic marker, lysine methylation can interact with important proteins such as p53 and NF-kB, and regulate the chromatin structure and transcription functions. Due to the lack of a robust synthetic method for the preparation of proteins with dimethyllysine, many important biological questions remain unclear. Several chemical biology approaches have been developed, but none of them is perfect. Here, we plan to develop a robust and easy-applied approach for dimethyllysine installation into proteins with the combination of noncanonical amino acid incorporation (ncAA) and bioorthogonal reactions. Nε-(4-azidobenzoxycarbonyl)-δ,ε-dehydrolysine (AcdK) is incorporated as a precursor of allysine (AlK), which can further undergo reductive amination reaction with dimethylamine to generate dimethyllysine in its native structure. P53 and histone H3 are used as model proteins showing the dimethyllysine generated by our method can be recognized exactly the same as native ones.

Chemical biology approach for dimethyllysine incorporation into proteins

253rd National Meeting (2017)

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