Bacterial ribosome and associated protein synthesis machinery

Bacterial protein synthesis occurs on ribosomes in the bacterial cytoplasm. Unlike eukaryotes, bacteria lack a nucleus and have free-floating circular DNA called a nucleoid. The process involves transcription of DNA to mRNA and subsequent translation into proteins. Bacterial protein synthesis can be divided into four main steps: initiation, elongation, termination, and ribosome recycling[2][3]. The bacterial ribosome (70S) consists of 30S and 50S subunits and contains the peptidyl transferase center (PTC) that catalyzes peptide bond formation[2]. The process begins at the start codon (AUG) with the formation of a 30S initiation complex involving mRNA, 30S ribosomal subunit, Met-tRNA, initiation factors, and GTP[3][4]. The Shine-Dalgarno sequence near the start codon serves as the ribosome binding site[3]. During elongation, tRNAs with anticodons complementary to mRNA codons deliver amino acids to the ribosome, which catalyzes peptide bond formation between adjacent amino acids. The ribosome moves along the mRNA, adding up to 15 amino acids per second to the growing polypeptide chain[4]. Multiple ribosomes (up to 50) can simultaneously translate a single mRNA molecule, forming a polysome[4]. Termination occurs when the ribosome encounters a stop codon, resulting in the release of the completed polypeptide chain[4]. This machinery represents one of the major targets for antibiotics, with different drugs targeting specific steps in the process[2][6][8].

Other names

Bacterial translational machineryBacterial protein synthesis apparatusBacterial translation system

Inhibition of 30S ribosomal subunit function Blocking aminoacyl-tRNA binding to the A site Disruption of 30S initiation complex formation Interference with 70S ribosome formation Prevention of elongation during protein synthesis