Molecular visualization of yeast phenylalanine tRNA (1EVV)

Transfer RNA (tRNA) are small RNAs, usually about 74—95 nucleotides, among which minor nucleotides, e.g. pseudouridine, dihydrouridine, and modified nucleotides (e.g. methylated and dimethylated adenine, cytosine, guanine) are frequently found. tRNA binds and transfers amino acids to the ribosomal site of protein synthesis where a polypeptide chain grows. The accepting site of tRNA is charged with a specific amino acid by a special enzyme aminoacyl tRNA synthetase.

The secondary structure “cloverleaf” of tRNA is achieved with maximum of Watson-Crick pairs and four base-paired stems formed. Most tRNAs have four stems (acceptor, D, and anticodon, T) and three non-base-paired loops (TpsiC, D, and anticodon). The acceptor stem stacks onto the TpsiC stem to form an acceptor branch (turned to the left in the picture), while the other two stems also interact to form the anticodon branch (turned down in the picture).

Anticodon is a part of tRNA consisted of three nucleotides that correspond to a certain codon on the mRNA. During translation a codon of mRNA is recognized by the codon of approaching the ribosome tRNA. At this stage the enzymatic machinery of the ribosome performs a number of reactions, resulting in the amino acid residue to be added to the growing peptide chain.

In the picture you can see the tertiary structure of yeast phenylalanine tRNA. The spatial arrangement of tRNA phosphate backbone is shown in green and Watson-Crick and non-canonical base pairs are shown in purple.
The image size is 6000×6000 pixels.