MoBio Structure of tRNA Chapter 3

The major role of tRNA is to translate mRNA sequence into amino acid sequence. A tRNA molecule consists of 70-80 nucleotides. Its secondary and tertiary structures are shown in Figures 3-C-2 and 3-C-3, respectively. Some nucleotides in tRNA have been modified, such as dihydrouridine (D), pseudouridine (ψ), and inosine (I). In dihydrouridine, a hydrogen atom is added to each C5 and C6 of uracil. In pseudouridine, the ribose is attached to C5, instead of the normal N1. Inosine plays an important role in codon recognition. In addition to these modifications, a few nucleosides are methylated.

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Figure 3-C-2. The secondary structure of tRNA. Blue color indicates modified nucleotides, with "m" representing "methylated". Anticodon is the trinucleotides complementary to a codon on mRNA.

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Figure 3-C-3. The tertiary structure of tRNA. PDB ID = 1TN2.