Bacterial 50S ribosomal assembly precursors (pre-50S) (pre-50S)

Bacterial 50S ribosomal assembly precursors are intermediate ribonucleoprotein complexes formed during the multi-step biogenesis of the large (50S) ribosomal subunit. This intricate process requires the precise folding of 23S and 5S ribosomal RNA (rRNA) and the hierarchical incorporation of approximately 33 ribosomal proteins, often assisted by various assembly factors like GTPases, helicases, and chaperones (Shajani et al., 2011; Davis & Williamson, 2017). These precursors are essential for maintaining the cellular supply of functional ribosomes; any disruption in their maturation leads to a rapid decline in protein synthesis capacity and bacterial growth arrest (Champney, 2001). While many classic antibiotics, such as macrolides (e.g., erythromycin) and ketolides, are primarily recognized for inhibiting translation at the mature ribosome, they also bind to these assembly intermediates, preventing their progression into functional subunits (McGinness & Champney, 1999; Usary & Champney, 2001). This dual mechanism of action—inhibiting both translation and ribosome formation—enhances their antimicrobial efficacy. Research into these precursors is vital for developing new classes of antibiotics that can bypass existing resistance mechanisms by targeting the assembly pathway itself rather than the mature protein-synthesis machinery (Britton, 2009).

Other names

50S assembly intermediatesImmature 50S subunitsPre-50S particlesLarge ribosomal subunit precursors

Inhibition of ribosome biogenesis by binding to assembly intermediates, preventing the transition to mature 50S subunits and depleting the cellular pool of functional ribosomes (Champney, 2001; McGinness & Champney, 1999).