50S ribosomal subunit of Mycobacterium tuberculosis

The **50S ribosomal subunit of Mycobacterium tuberculosis** is the large component of the bacterial ribosome, composed of 23S rRNA, 5S rRNA, and approximately 35 proteins[6]. It participates in protein biosynthesis by catalyzing peptide bond formation and coordinating translation. Unique structural features (such as specific additional ribosomal proteins and rRNA extensions) distinguish the mycobacterial 50S subunit from those of other bacteria, influencing interactions with both regulatory factors and antibiotics[4][6]. This subunit is a validated therapeutic target, as it is critical to cell viability and targeted by multiple classes of antibiotics (notably macrolides, aminoglycosides, and tuberactinomycin antibiotics). Resistance may arise through drug-induced modifications of the ribosome, most prominently through methylation of 23S rRNA by TlyA, impacting drug binding and efficacy[1][3][5][7].

Other names

50S large ribosomal subunitMycobacterium tuberculosis 50S ribosomal subunitMtb 50S ribosomal subunit

Inhibition of protein synthesis: Antibiotics such as capreomycin and clarithromycin bind to the 50S subunit, interfering with peptidyl transfer and/or translocation steps of translation, inhibiting bacterial protein synthesis[3][6][7]. Resistance modification: Methyltransferases (such as TlyA) can methylate specific nucleotides in rRNA, altering 50S subunit conformation and reducing antibiotic binding, leading to resistance[1][3][5].