Serine tRNA (5TRA) - Translation is the process of protein synthesis that takes place on ribosomes. During translation the sequence of nucleotides in an mRNA is used as a template to determine the sequence of amino acids in the polypeptide that the mRNA encodes. Each "codon" is composed of 3 nucleotides that specifies only one amino acid but each type of amino acid can be encoded by 1 to 6 codons (since there are 20 amino acids used in proteins and a total of 64 possible combinations of 4 nucleotides in groups of 3). The links between the information in codons and the amino acid each one encodes are the tRNA or transfer RNA molecules. tRNAs are composed of 73 to 93 nucleotides that fold into a L-shaped structure stabilized by base pairing within the molecule. On one end of the "L" is the "anticodon" consisting of three nucleotides that form base pairs with the codon of the mRNA. An amino acid is attached to the other end of the tRNA. When the correct tRNA binds to a codon of an mRNA, a peptide bond is formed between the amino acid and the growing polypeptide chain. After the tRNA loses its amino acid, it is free to diffuse away to have another amino acid attached.

In the picture below the serine tRNA of yeast is pictured with the anticodon at the bottom and the amino acid binding site at the top right. Notice the regions of base pairing within the structure, especially in the upper right section.

8/22/04 Copyright (C) 2004, Jonathan Monroe, monroejd@jmu.edu. All rights reserved.
URL: http://csm.jmu.edu/biology/courses/bio220/strna.html