GlutamyltRNA

Glutamyl-tRNA, often abbreviated as Glu-tRNA, is the tRNA molecule charged with the amino acid glutamate. It is produced when the enzyme glutamyl-tRNA synthetase (GluRS) transfers glutamate from glutamyl-tRNA to the corresponding tRNA, a reaction known as aminoacylation. The resulting Glu-tRNA carries glutamate to the ribosome, where it participates in translation and delivers the amino acid for incorporation into a growing polypeptide.

In the genetic code, the codons for glutamate are GAA and GAG. Glu-tRNA recognizes these codons at the ribosome, aided by elongation factors that form a ternary complex with the charged tRNA and GTP, ensuring accurate delivery during protein synthesis.

Glu-tRNA is also involved in a notable pathway in bacteria and some archaea. Some organisms lack a dedicated glutaminyl-tRNA synthetase (GlnRS) and instead use a two-step indirect route: Glu-tRNA^Gln is first formed by a non-discriminating GluRS, after which the GatCAB amidotransferase converts it to Gln-tRNA^Gln, enabling incorporation of glutamine during translation.

Enzymatic fidelity and editing play roles in maintaining accuracy. GluRS enzymes vary in their tRNA recognition and may possess editing activities to prevent misacylation with non-cognate amino acids. Glu-tRNA is widespread across bacteria, archaea, mitochondria, and chloroplasts, reflecting its fundamental function in translating genetic information into proteins.

Overall, Glu-tRNA serves as a key intermediary in protein synthesis, linking the genetic code to the incorporation of glutamate into polypeptides, and it participates in organism-specific variations of tRNA charging and aminoacylation pathways.