Functions of inhibitors

Question 1

What is the function of α-amanitin?

Answer 1

Poison. Interferes with RNAPII in prokaryotes by disrupting translocation of RNA-DNA complex through structure.

Question 2

What is the function of actinomycin D?

Answer 2

Chemothrapeutic agent. Intercalates into DNA and prevents initiation of transcription.

Question 3

What is the function of rifamycin?

Answer 3

Antibiotic. Binds to prokaryotic RNAP and inhibits bacterial transcription (probably blocks chain elongation by binding to β-subunit).

Question 4

What is the function of ricin?

Answer 4

Glycosidase activity removes adenosine from 28S RNA, inactivating ribosome and thus inhibiting translation.

Question 5

What is the function of diptheria toxin?

Answer 5

Inhibits activity of eEF-2, preventing ribosomal translocation on mRNA and thus translation.

Question 6

What is the function of streptomycin?

Answer 6

• Antibiotic
• At high concentrations, it binds to and inhibits 30S subunit of bacterial ribosome
• At lower concentrations, it causes misreading of mRNA

Question 7

What is the function of tetracycline?

Answer 7

• Antibiotic

- Inhibits binding of aminoacyl-tRNA to bacterial 30S subunits.

Question 8

What is the function of oxazolidines?

Answer 8

• Antibiotic

- Inhibits formation of Met-tRNAi-30S initiation complex

Question 9

What is the function of chloramphenicol?

Answer 9

• Antibiotic

- Inhibits peptidyl transferase activity of 50S subunit

Question 10

What is the function of erythromyocin?

Answer 10

• Antibiotic
• Binds to 50S subunit at the exit tunnel of free tRNA molecules and prevents them from being released. This blocks the progression of ribosome complex.