Maturation and architecture of tRNA

The global organization of the tRNA structure is highly conserved in all forms of life. Prominent features of the tRNA structure, as shown in the figure, include: an acceptor stem with the CCA trinucleotide at the 3' end (the site of aminoacylation and trans-peptidation reactions in the protein-biosynthesis cycle); a D loop (named after a tandem dihydrouridine modification, labelled "D" in the figure, which is commonly found in this loop); an anticodon loop that includes the anticodon, which is a nucleotide triplet responsible for recognition of a coding triplet in mRNA, and the T loop, named after the highly conserved triplet. Filled circles represent nucleotides that are not usually modified; open circles represent commonly modified nucleotides other than D, T and psi.