Antibiotics often target the gene expression machinery of the bacteria they targ

Question

Antibiotics often target the gene expression machinery of the bacteria they target. Antibiotics have been useful in elucidating the steps of protein synthesis. If you have an artificial messenger RNA with the sequence: 5’ AUGUUUUUUUUUUUU…3’, it will produce the following polypeptide in a cell-free, protein-synthesizing system:

fMet-Phe-Phe-Phe-Phe

In your search for new antibiotics you find one called putyermycin, which blocks protein synthesis. When you try it with your artificial mRNA in a cell-free system, the product is fMet-Phe. What step in translation elongation does putyermycin affect? Explain your answer.

Explanation / Answer

Antibiotics act at the level of the ribosomal level .Puromycin is a well known inhibhitor of protein synthesis in a cell free system. It structure is analogous to the aminoacyl t RNA leading to premature release of the unfinished polypeptide protein synthesis as polypeptideyl puromycin derivatives. It resembles the A site of the t RNA but product will not participate in translocation to the P site in a reaction which peptidyl transferases catalyses the attachment of peptidyl chain to free amino group of the puromycin. The lack of translocation results in dissociation form the ribosomes and early peptidyl termination . this leads to production of turnicated , non functional polypeptide .

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.