Question

Why is puromycin not useful as an antibiotic to treat bacterial infections in humans?

Short answer

Puromycin is not useful as an antibiotic to treat bacterial infections in humans because its mechanism of action does not discriminate between bacterial and human ribosomes. Although it effectively inhibits bacterial protein synthesis, it also disrupts human protein synthesis, leading to potentially harmful side effects. As a result, it is not a suitable choice for treating bacterial infections in humans.

Step-by-step solution

Background on Antibiotics and Puromycin

Antibiotics are substances that help in killing or slowing down the growth of bacteria, allowing the immune system to clear the infection more effectively. Puromycin is an antibiotic produced by Streptomyces alboniger, and it has a similar structure to aminoacyl-tRNAs (transfer RNA molecules with an amino acid attached). This similarity is the basis of how it works as an antibiotic.

Mechanism of Action of Puromycin

Puromycin inhibits protein synthesis by acting as a false aminoacyl-tRNA molecule. It enters the A-site of the ribosome, binds to the growing peptide chain attached to the tRNA in the P-site, and causes premature termination of the newly formed protein. Essentially, it disrupts the normal process of protein synthesis, leading to the production of nonfunctional or incomplete proteins.

Effect of Puromycin on Bacterial and Human Cells

The problem with using puromycin as an antibiotic in humans is that it does not discriminate between bacterial and human ribosomes. Both bacterial and human cells rely on protein synthesis for crucial cellular processes, and puromycin will inhibit protein synthesis in both types of cells. As a result, using puromycin in humans can also disrupt the normal cellular functions of their own cells, leading to toxic effects in addition to the desired antibacterial properties.

Conclusion

In conclusion, puromycin is not useful as an antibiotic to treat bacterial infections in humans because its mechanism of action does not discriminate between bacterial and human ribosomes. While it is effective in inhibiting bacterial protein synthesis, it also disrupts human protein synthesis, leading to potentially harmful side effects. Thus, it is not a suitable choice for treating bacterial infections in humans.