Diagram the mode of action of puromycin.

Name: Problem 7, Chapter 18: Molecular Biology
Uploaded: 2025-08-08T16:37:01-08:00
Channel: Rashmi Sinha
Description: Diagram the mode of action of puromycin.

Key Concepts

Protein Synthesis

Protein synthesis is the process by which cells build proteins by translating the genetic information encoded in messenger RNA (mRNA) into a sequence of amino acids. This complex process takes place on ribosomes and involves initiation, elongation, and termination phases that together ensure the precise assembly of polypeptide chains.

Ribosomal Peptidyl Transferase Activity

Ribosomal peptidyl transferase is the enzymatic function found in the ribosome’s large subunit that catalyzes the formation of peptide bonds between amino acids. This activity is central to the elongation phase of protein synthesis, enabling the sequential addition of amino acids to the growing polypeptide chain.

Aminoacyl-tRNA Mimicry

Aminoacyl-tRNA mimicry refers to the ability of certain molecules to structurally and functionally resemble aminoacyl transfer RNAs (tRNAs). By mimicking these key components of the translation machinery, these molecules can gain access to the ribosome’s active sites and disrupt normal protein synthesis.

Premature Chain Termination

Premature chain termination is a process wherein the elongation of a polypeptide is interrupted before the protein is fully synthesized. This results from the incorporation of molecules that induce the early release of the incomplete polypeptide, thereby halting the normal progression of translation.

Puromycin Mechanism

Puromycin is an antibiotic that exploits aminoacyl-tRNA mimicry by entering the ribosomal A-site during translation. Once incorporated into the growing polypeptide, it causes premature chain termination by releasing the nascent protein due to its inability to form further peptide bonds. This mechanism of action effectively disrupts protein synthesis and highlights a key target for antibiotic intervention.

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