Question

Clearly explain the biochemical mechanism by which humans get well from bacterial infection after taking puromycin.

Answer 1

Answer:

A bacterial pathogen is said to have caused infections within the different body parts of the humans. In order to have caused an infection, bacteria would need to form their own proteins within the host body.

In order for the formation of the bacterial proteins; a bacteria exhibits the process of central dogma that is;

Initially the bacterial DNA gets duplicated (process: replication),

Then the bacterial DNA forms the RNA transcript (process: transcription), and lastly

From the RNA, the bacteria synthesize their own proteins. (Process: translation)

Only after the expression of the bacterial proteins within the host body, a bacterium is said to have caused infections.

As a remedial mechanism to the infections caused by the bacterium, different antibiotics are prescribed which have different mechanisms of their actions thereby hindering the further growth of the bacterium. One such example is that of an antibiotic; Puromycin.

Mechanism of action of Puromycin:

Puromycin is a broad spectrum bacterium; that is the antibiotic can be used in order to treat the infections caused by a number of different gram positive bacterial species.

It remains produced by a specific group of bacterial species namely Streptomyces alboniger.

The antibiotic is known to mediate its function by terminating the process of bacterial protein synthesis within the host cells. When bacterial proteins will not be formed, the infections also will not be caused.

For protein synthesis, the different codons present within the mRNA needs to be decoded within the A and the P sites of the ribosomes and then the corresponding amino acids are brought to them by the tRNA which base pairs with the codons by the anticodon loop.

Puromycin gets bound to the  C- terminus of the growing peptide chain thus preventing the further attachment of the amino acids. Since amino acids are not brought afterwards, this leads to the premature termination of the protein polypeptide chain leading to the formation of the truncated bacterial protein.

The direction of protein synthesis is from 5'-3' direction; that is the new upcoming amino acids are always brought to the 3' direction of the growing polypeptide chain.

Summary: antibiotic puromycin inhibits the bacterial protein synthesis by leading to the formation of truncated proteins by getting bound to the C-terminus of the growing polypeptide chain.

Since proteins will not be formed, bacteria would lose their potential of causing infections within the human body.