A genetically encoded photocaged N -methyl-l-lysineThis article is part of the 2010 Molecular BioSystems 'Emerging Investigators' issue: highlighting the work of outstanding young scientists at the chemical- and systems-biology interfaces.Electronic supplementary information (ESI) available: Synthesis and characterization data of 6 and 8, DNA and protein sequences, plasmid construction, the pRS1 library construction, selections, Supplementary Tables, Schemes, and Figures. See DOI: 10.1039/c00215

A photocaged N -methyl- l -lysine has been genetically incorporated into proteins at amber codon positions in Escherichia coli using an evolved pyrrolysyl-tRNA synthetase-pylT pair. Its genetic incorporation and following photolysis to recover N -methyl- l -lysine at physiological pH provide a convenient method for the biosynthesis of proteins with monomethylated lysines at specific sites. Using an evolved pyrrolysyl-tRNA synthetase-pylT pair, a photocaged N -methyl- l -lysine has been genetically incorporated into proteins at amber codons in Escherichia coli .