Author ORCID Identifier

Defense Date


Document Type


Degree Name

Doctor of Philosophy



First Advisor

Dr. T. Ashton Cropp


Post-translational modifications (PTMs) play a significant role in regulating cell signaling and regulating the inner cellular environment. The study of PTMs and their primary biological functions is critical for the development of new medicines targeting the pathways and biomolecules responsible for the PTMs.

Previous studies revealed the direct coupling of the β -hydroxybutyryl lysine (KBHB) modification with the gene expression. KBHB in histone proteins links metabolism to epigenetics and gene expression and enables to study in-depth, how cell metabolism controls the gene expression and vice versa. Similar novel histone modification, KLac, attracts a special interest since lactic acid is generated highly in cancer cells due to the huge energy requirement. To study the PTM in-depth, it is critical to obtain homogeneously modified proteins. This study presents a methodology to obtain acylated lysine modified form of proteins in a homogenous composition.

This thesis reports the synthesis of Nε-β-hydroxybutyryl lysine (KBHB), KLac, and several other lysine PTMs. Synthesized lysine PTMs were screened using a small library of pyrrolysyl-tRNA Synthetase derived variants to find an enzyme that can recognize the lysine PTMs as substrates to aminoacylate the tRNAPylCUA. Finally, the discovered PylRS/tRNAPyl pair was used for the genetic incorporation of the synthesized lysine PTMs and encoding them into proteins as a response to the amber stop codon. This method enabled us to obtain a homogenous composition of proteins with the post-translationally modified form, which is focused site-specifically. This will greatly enable further studies directed at understanding the biological function of these PTMs.


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Available for download on Friday, May 16, 2025