A genetically encoded photocaged Nepsilon-methyl-L-lysine

Area of Science:

• Biochemistry
• Molecular Biology
• Synthetic Biology

Background:

• Site-specific protein modification is crucial for understanding protein function.
• Current methods for introducing post-translational modifications like methylation can be inefficient or lack specificity.
• Lysine methylation plays significant roles in various cellular processes.

Purpose of the Study:

• To develop a novel method for the site-specific genetic incorporation of N(epsilon)-methyl-L-lysine into proteins.
• To demonstrate the utility of this method in Escherichia coli.
• To enable the biosynthesis of proteins with controlled lysine methylation patterns.

Main Methods:

• Utilized an evolved pyrrolysyl-tRNA synthetase-pylT pair for amber codon suppression.
• Genetically encoded a photocaged N(epsilon)-methyl-L-lysine analog.
• Performed photolysis to release the N(epsilon)-methyl-L-lysine within the protein structure at physiological pH.

Main Results:

• Successfully incorporated the photocaged N(epsilon)-methyl-L-lysine into proteins at specific sites in E. coli.
• Demonstrated efficient release of N(epsilon)-methyl-L-lysine upon photolysis under physiological conditions.
• Confirmed the site-specific monomethylation of lysine residues within the target proteins.

Conclusions:

• Developed a convenient and efficient method for the site-specific biosynthesis of proteins containing monomethylated lysines.
• This genetic incorporation and photolysis strategy offers a powerful tool for studying the functional roles of lysine methylation.
• The method is applicable to various protein targets and holds potential for broader applications in chemical biology and protein engineering.