“…Generally, tRNA AsnE2 and tRNA GluE2 are used to incorporate a variety of N -methyl (refs , , , , , , − , , , , − , , , , , , and − ), linear N -alkyl, ,, branched N -alkyl, , functionalized alkyl chain (azido, alkyne, cyano, etc. ), , and cyclic N -alkyl amino acids (Figure ).…”