lysyl-tRNA aminoacylation

Definition

Target type: biologicalprocess

The process of coupling lysine to lysyl-tRNA, catalyzed by lysyl-tRNA synthetase. The lysyl-tRNA synthetase is a class-II synthetase. The activated amino acid is transferred to the 3'-OH group of a lysine-accetping tRNA. [GOC:mcc, ISBN:0716730510]

Lysyl-tRNA aminoacylation is a crucial step in protein synthesis, ensuring the accurate incorporation of lysine residues into growing polypeptide chains. This process involves the attachment of lysine (Lys) to its corresponding transfer RNA (tRNA), specifically tRNA^Lys. The reaction is catalyzed by a specific enzyme known as lysyl-tRNA synthetase (LysRS).

The process begins with the binding of both Lys and tRNA^Lys to the active site of LysRS. The enzyme possesses two distinct binding sites, one for Lys and the other for tRNA^Lys. The amino acid, Lys, first enters the active site and interacts with specific residues within the enzyme. This interaction facilitates the activation of Lys by ATP, converting it into lysyl adenylate (Lys-AMP). Lys-AMP remains bound to LysRS, poised for the next step.

Simultaneously, tRNA^Lys binds to the enzyme's tRNA binding site. The recognition of tRNA^Lys by LysRS is highly specific, ensuring the correct amino acid is attached to the correct tRNA. This specificity is achieved through a complex interplay of interactions between the enzyme and the tRNA's anticodon loop and acceptor stem.

Once both Lys-AMP and tRNA^Lys are bound to LysRS, the transfer of Lys from Lys-AMP to the 3' end of tRNA^Lys takes place. This reaction involves the formation of a covalent bond between the carboxyl group of Lys and the 2'- or 3'-hydroxyl group of the terminal adenosine residue of tRNA^Lys. This newly formed lysyl-tRNA^Lys molecule is then released from LysRS, ready to participate in protein synthesis.

The accuracy of lysyl-tRNA aminoacylation is essential for the fidelity of translation. Mischarging, where the wrong amino acid is attached to tRNA, can lead to the incorporation of incorrect amino acids into proteins, resulting in dysfunctional or non-functional proteins. To prevent mischarging, LysRS employs proofreading mechanisms that ensure the correct amino acid is selected and attached to tRNA.

In summary, lysyl-tRNA aminoacylation is a critical step in protein synthesis that involves the specific attachment of lysine to tRNA^Lys. This process is catalyzed by LysRS, which employs precise recognition and proofreading mechanisms to ensure the accuracy and efficiency of protein synthesis.'
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Proteins (1)

Compounds (7)