biostudies-literatureArpin DFonds de Recherche du Québec – SantéFonds de Recherche du Québec - SantéMcGill UniversityCanada Foundation for InnovationCanadian Institutes of Health ResearchCIHRgkae1197https://www.ebi.ac.uk/biostudies/studies/S-EPMC11754645biostudies-literatureUnknown53(2)The intricate process of 50S ribosomal subunit assembly in Bacillus subtilis involves multiple parallel pathways converging into a crucial intermediate known as the 45S particle. RbgA and YphC, play pivotal roles in completing the maturation of the functional sites in the 45S particle. In this work, we found that RbgA and YphC can independently bind the 45S particle with high affinity, but when RbgA binds first to the particle, it significantly increases the binding affinity of YphC. Using cryo-electron microscopy, we determined that the changes exerted by RbgA and YphC when binding independently closely resemble those observed when the two factors bind to the 45S particle simultaneously. However, the structural analysis revealed that RbgA binding causes a conformational change that uncoveNucleic acids researchThe binding of RbgA to a critical 50S assembly intermediate facilitates YphC function in bacterial ribosomal assembly.PMC11754645PJT-180305Basu KArpin DPalacios AOrtega JfalseThe binding of RbgA to a critical 50S assembly intermediate facilitates YphC function in bacterial ribosomal assembly.The intricate process of 50S ribosomal subunit assembly in Bacillus subtilis involves multiple parallel pathways converging into a crucial intermediate known as the 45S particle. RbgA and YphC, play pivotal roles in completing the maturation of the functional sites in the 45S particle. In this work, we found that RbgA and YphC can independently bind the 45S particle with high affinity, but when RbgA binds first to the particle, it significantly increases the binding affinity of YphC. Using cryo-electron microscopy, we determined that the changes exerted by RbgA and YphC when binding independently closely resemble those observed when the two factors bind to the 45S particle simultaneously. However, the structural analysis revealed that RbgA binding causes a conformational change that uncove2025-01-01T00:00:00Z2025 Jan2026-04-18T03:25:11.523Z2025-04-04T11:47:15.85ZS-EPMC117546453965804310.1093/nar/gkae1197