glutamyl-tRNA aminoacylation

Definition

Target type: biologicalprocess

The process of coupling glutamate to glutamyl-tRNA, catalyzed by glutamyl-tRNA synthetase. The glutamyl-tRNA synthetase is a class-I synthetase. The activated amino acid is transferred to the 2'-OH group of a glutamic acid-accetping tRNA. The 2'-O-aminoacyl-tRNA will ultimately migrate to the 3' position via transesterification. [GOC:mcc, ISBN:0716730510]

Glutamyl-tRNA aminoacylation is a crucial step in protein synthesis, specifically in the process of translation. This process ensures the accurate delivery of the amino acid glutamate (Glu) to the ribosome, where it is incorporated into the growing polypeptide chain.

The process begins with the enzyme glutamyl-tRNA synthetase (GluRS), which specifically recognizes both glutamate and its corresponding tRNA molecule, tRNA^Glu. This recognition is essential for ensuring fidelity in protein synthesis.

GluRS catalyzes the attachment of glutamate to the 3' end of tRNA^Glu in a two-step reaction:

1. **Activation of glutamate:** GluRS first binds to glutamate and ATP (adenosine triphosphate), which provides the energy required for the reaction. Glutamate is then adenylated, forming glutamyl-AMP (adenosine monophosphate).

2. **Transfer of glutamate to tRNA^Glu:** The activated glutamate, still bound to GluRS, is then transferred to the 3' acceptor stem of tRNA^Glu. This step involves the formation of a high-energy ester bond between the carboxyl group of glutamate and the 2'- or 3'-hydroxyl group of the terminal adenosine residue in tRNA^Glu.

The resulting glutamyl-tRNA^Glu molecule is now ready to participate in protein synthesis at the ribosome. During translation, the ribosome uses the codon sequence in mRNA to recruit the appropriate tRNA molecule carrying its corresponding amino acid. In the case of glutamyl-tRNA^Glu, the ribosome recognizes the codon GAA or GAG, which codes for glutamate. The glutamyl-tRNA^Glu then delivers glutamate to the ribosome, where it is incorporated into the growing polypeptide chain.

Glutamyl-tRNA aminoacylation is a highly regulated process, with several mechanisms in place to ensure accuracy. For instance, GluRS has a proofreading function that helps to prevent mischarged tRNAs from entering the translation process. This proofreading activity ensures that only correctly charged tRNAs are used in protein synthesis, minimizing errors and maintaining the integrity of the polypeptide chain.

Errors in glutamyl-tRNA aminoacylation can lead to the incorporation of incorrect amino acids into proteins, resulting in dysfunctional or non-functional proteins. These errors can have significant consequences for cellular function and can contribute to a range of diseases.'
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Proteins (1)

Compounds (1)