tRNA modification

Definition

Target type: biologicalprocess

The covalent alteration of one or more nucleotides within a tRNA molecule to produce a tRNA molecule with a sequence that differs from that coded genetically. [GOC:curators]

tRNA modification is a crucial biological process that involves the enzymatic alteration of transfer RNA (tRNA) molecules. These modifications play vital roles in enhancing tRNA stability, influencing codon recognition, and ensuring accurate protein synthesis.

The process typically involves a series of enzymatic reactions that attach various chemical groups to specific nucleotides within the tRNA structure. These modifications can occur at different positions, including the anticodon loop, the D-loop, the TψC loop, and the acceptor stem.

**Common tRNA modifications include:**

* **Base modifications:**
* **Methylation:** Addition of a methyl group (-CH3) to a base. Examples include N1-methyladenosine (m1A), N6-methyladenosine (m6A), and 7-methylguanosine (m7G).
* **Deamination:** Conversion of an amino group (-NH2) to a keto group (=O). Examples include inosine (I) from adenosine and pseudouridine (ψ) from uridine.
* **Thiolation:** Replacement of an oxygen atom with a sulfur atom. Examples include 2-thiouridine (s2U) and 4-thiouridine (s4U).
* **Ribose modifications:**
* **Methylation:** Addition of a methyl group to the 2'-hydroxyl group of a ribose sugar. Examples include 2'-O-methyluridine (Um) and 2'-O-methylcytidine (Cm).
* **Pseudouridylation:** Isomerization of uridine to pseudouridine, where the uracil base is attached to the ribose sugar at the C5 position instead of the N1 position.

**Functions of tRNA modifications:**

* **Enhanced tRNA stability:** Modifications can protect tRNA from degradation, increase its thermal stability, and promote its proper folding.
* **Improved codon recognition:** Modifications in the anticodon loop can influence the strength of codon-anticodon interactions, allowing for fine-tuning of translation efficiency.
* **Accurate protein synthesis:** Modifications can contribute to the fidelity of translation by ensuring correct amino acid incorporation.
* **Regulation of translation:** Some modifications can act as regulatory switches, affecting the translation of specific mRNAs.

The diversity and specificity of tRNA modifications are highly regulated and vary depending on the organism, cell type, and environmental conditions. Dysregulation of tRNA modification processes can have significant consequences for cellular function and can contribute to various diseases.'
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Proteins (2)

Compounds (2)