Mycobacterium tuberculosis 50S ribosomal subunit (Mtb 50S subunit)

The Mycobacterium tuberculosis 50S ribosomal subunit is the larger component of the bacterial 70S ribosome and is essential for protein biosynthesis (Li et al., 2017, Nature). It consists of the 23S ribosomal RNA (rRNA), the 5S rRNA, and approximately 33 ribosomal proteins that provide the structural framework for translation (Yang et al., 2017, Science). The subunit houses the peptidyl transferase center (PTC), the site where amino acids are enzymatically joined, and the exit tunnel through which the newly formed protein leaves the ribosome (Wilson, 2014, Nature Reviews Microbiology). Because its structure is distinct from the eukaryotic 60S subunit, it serves as a highly effective target for several classes of antibiotics, most notably the oxazolidinones like linezolid. These drugs bind to the 23S rRNA to block the initiation or elongation phases of translation, effectively inhibiting the growth of M. tuberculosis (Poehlsgaard & Douthwaite, 2005, Nature Reviews Microbiology). Understanding the specific architecture of the Mtb 50S subunit is critical for overcoming multi-drug resistant tuberculosis (MDR-TB) through the design of next-generation inhibitors.

Other names

Large ribosomal subunit50S subunit of the M. tuberculosis ribosomeMtb 50S

Inhibition of bacterial protein synthesis by binding to the 23S rRNA within the peptidyl transferase center (PTC) or the nascent peptide exit tunnel (NPET), which prevents peptide bond formation or the translocation of the growing polypeptide chain (Wilson, 2014, Nature Reviews Microbiology; DrugBank).