From: Evidence from glycine transfer RNA of a frozen accident at the dawn of the genetic code
 | Amino acids in proposed order of incorporation into genetic code | Reported hairpin amino-acylation | Established stereochemical relationship with anticodon |
---|---|---|---|
 | glycine | + |  |
 | alanine | + |  |
 | aspartic acid | + |  |
early | valine | + | Â |
 | proline |  |  |
 | serine | + |  |
 | glutamic acid |  |  |
 | threonine |  |  |
 | leucine |  | + |
 | arginine |  | codon |
 | asparagine |  |  |
 | isoleucine | + | anticodon/codon |
 | glutamine | + | - |
 | histidine | + | + |
 | lysine |  |  |
 | cysteine | + |  |
late | phenylalanine | Â | + |
 | tyrosine | + | + |
 | methionine | + |  |
 | tryptophan |  | + |