proline-tRNA ligase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: ATP + L-proline + tRNA(Pro) = AMP + diphosphate + L-prolyl-tRNA(Pro). [EC:6.1.1.15]

Proline-tRNA ligase activity is a fundamental process in protein synthesis, specifically in the translation stage. It involves the accurate and efficient attachment of the amino acid proline to its cognate transfer RNA (tRNA) molecule. This process is essential for ensuring the correct sequence of amino acids in the polypeptide chain during protein synthesis.

Here are the key steps involved in proline-tRNA ligase activity:

1. **Binding of Proline and tRNAPro:** The enzyme first binds to both proline and tRNAPro, the specific tRNA molecule that carries proline. This binding is highly specific, ensuring that the correct amino acid is attached to the correct tRNA.

2. **Activation of Proline:** The enzyme then activates proline by attaching it to a molecule of adenosine monophosphate (AMP) in a reaction that requires ATP hydrolysis. This process forms prolyl-AMP, an activated form of proline.

3. **Transfer of Proline to tRNAPro:** The activated proline is then transferred from prolyl-AMP to the 3'-end of tRNAPro, specifically to the 2'- or 3'-hydroxyl group of the terminal adenosine. This transfer reaction is also highly specific and requires the presence of a divalent metal ion, typically Mg2+.

4. **Release of AMP and Enzyme:** After the transfer reaction, AMP and the enzyme are released, leaving the charged tRNAPro ready to participate in protein synthesis.

The proline-tRNA ligase enzyme plays a crucial role in maintaining the fidelity of translation, ensuring that the correct amino acids are incorporated into the growing polypeptide chain. Any errors in this process can lead to the production of non-functional or even harmful proteins.

In addition to its role in protein synthesis, proline-tRNA ligase activity is also involved in various other cellular processes, including:

* **Regulation of gene expression:** The enzyme can interact with other proteins involved in gene regulation, influencing the expression of certain genes.

* **Cell signaling:** Proline-tRNA ligase activity can be influenced by various intracellular signals, contributing to the overall cellular response.

* **Cellular stress response:** The enzyme can be upregulated in response to cellular stress, potentially playing a protective role.

The molecular function of proline-tRNA ligase activity is therefore critical for the survival and proper functioning of all living organisms.'
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Proteins (2)

Compounds (1)