prolyl-tRNA aminoacylation

Definition

Target type: biologicalprocess

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

Prolyl-tRNA aminoacylation is a crucial step in protein synthesis, where the amino acid proline is attached to its cognate tRNA molecule, specifically tRNAPro. This process ensures that the correct amino acid is incorporated into the growing polypeptide chain during translation.

**1. Recognition and Binding:**
The process begins with the recognition and binding of proline to its specific synthetase enzyme, prolyl-tRNA synthetase (PRS). PRS exhibits high specificity for proline, distinguishing it from other amino acids. This recognition is mediated by specific interactions between the amino acid and the enzyme's active site.

**2. Activation of Proline:**
Once proline is bound to PRS, it undergoes activation. This involves the formation of an activated prolyl adenylate intermediate, where proline is linked to AMP (adenosine monophosphate) through a high-energy bond. ATP (adenosine triphosphate) provides the energy for this reaction, which is catalyzed by PRS.

**3. tRNAPro Binding:**
Simultaneously, tRNAPro binds to PRS. The tRNAPro molecule possesses a unique acceptor stem (3'-end) that is recognized by the synthetase. Specific interactions between the tRNAPro and the synthetase ensure the correct tRNA is selected.

**4. Proline Transfer:**
The activated prolyl adenylate then transfers proline from the enzyme to the 3'-end of tRNAPro. This transfer reaction involves the breaking of the high-energy bond between proline and AMP, releasing AMP as a byproduct. The resulting prolyl-tRNAPro molecule represents the charged tRNA ready to participate in translation.

**5. Proofreading:**
PRS employs proofreading mechanisms to ensure the accuracy of the aminoacylation process. These mechanisms involve the removal of incorrectly charged tRNA molecules or the hydrolysis of incorrectly attached amino acids. This proofreading activity enhances the fidelity of protein synthesis.

**6. Release of Charged tRNA:**
Once prolyl-tRNAPro is formed, it is released from the synthetase, ready to be transported to the ribosome. This charged tRNA will then be incorporated into the ribosome complex, where it will deliver the proline amino acid to the growing polypeptide chain during translation.

In summary, prolyl-tRNA aminoacylation is a highly specific and tightly regulated process that ensures the accurate incorporation of proline into proteins. It involves a series of steps, including recognition, activation, tRNA binding, proline transfer, proofreading, and release of the charged tRNA.'
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Proteins (1)

Compounds (1)