Insights into the mechanism and regulation of EgtD, a novel histidine methyltransferase from ergothioneine biosynthesis

My PhD thesis was centered around the biosynthetic origin of amino acid betaines. This ubiquitous and divers class of simple natural products plays key roles in many aspects of cellular life. These compounds are also increasingly recognized as green and sustainable additives in foods, cosmetics, detergents or ionic liquids. We discovered and characterized a class of N-methyl transferases that allow a select group of microorganisms to produce a variety of trimethylated amino acids. Through structural, kinetic and bioinformatics analysis we were able to delineate the catalytic mechanism and functional diversity of this novel enzyme family of betaine synthases. The results and insights of my thesis pave the way to explore the biological function of amino acid betaines, and also describe the first biotechnological approach for bulk production of these natural products.