Question

Synercid binds to sites on the 50S ribosomal subunit. Synercid interferes with

Multiple Choice

• replication.

• cell wall synthesis.

• transcription.

• translation.

Answer 1

Ans) The correct answer is Translation. Synercid is a streptogramin antibiotic used for treating infections caused by vancomycin resistant Staphylococci (VRSA) i.e vancomycin drug resistant strain of Staphylococci and other organisms.Synercid is a combination of 2 main ingredients i.e Quinupristin and Dalfopristin.

Synercid binds to the 50S ribosomal subunit and interferes with the process of Translation (Protein synthesis) in the above mentioned infection causing organisms.

Dalfopristin binds to the free site of peptidyl transferase enzyme (it catalyzes peptide bond formation between the Amino-acyl t-RNA in the P-site and the Amino-acyl t-RNA in the A-site of 50S subunit of the ribosome) and blocks the process of chain elongation of Translation because there will be no peptide bond formation.Thus, it affects the early Elongation step.

Quinipristin catalyzes the release of incomplete peptide chain which has been produced as a result of Translation elongation step. Thus, premature release of peptide chain also halts or stops the process of Translation particularly affecting the late Elongation step.