The tRNA type indicates one of the four possible groups ranking human mitochondrial tRNAs for their structural diversity and different tertiary interactions.

Further information about tRNA models can be found in this review.

In the following models, each tRNA nucleotide is numbered from 1 to 73, CCA-ending excluded; the anticodon triplet is marked with nucleotides 34 to 36.

Green circles represent all the nucleotide positions involved in post-transcriptional modifications; blue circles indicate nucleotide positions involved in tertiary folding, with interactions represented by lines; red circles represent nucleotide positions involved in tertiary folding and subject to post-transcriptional modifications.

Abbreviations: AS, acceptor stem; CL, anticodon loop; CS, anticodon stem; DL, dihydrouridine loop; TL, TψC loop; TS, TψC stem; VL, variable loop.

Model 0

The quasi-canonical cloverleaf structure, with standard D-loop/T-loop interaction.

Model 1

A single tRNA with an atypical anticodon stem.

Model 2

The most common among mt-tRNAs, characterized by loss of D-loop/T-loop interaction.

Model 3

A single tRNA with the lack of D-stem.