Table 2.

Summary of the Large Subunit Stages at Which the Modification Enzymes Perform Their Functions in 23S rRNA

		Ribosome Large Subunit Assembly Stages
Enzymea	23S rRNA Modificationb	Earlyc	Intermediate/ Latec
RluC	Ψ 957,2508,2584
RluD	Ψ 1919, 1921
RlmH	m3Ψ 1919
RlhA	OH5C 2505
RlmN	m2A 2507
RluE	Ψ 2461
RluF	Ψ 2608
RluB	Ψ 2609

^aEnzymes incorporating the modifications.

^bThe modification and the 23S rRNA sequence position.

^cThe 27S particle is an early-stage large subunit ribosomal assembly intermediate.²⁵ The modifications present in the 27S intermediate at similar levels as in the wild-type 50S large subunit indicate that the enzymes incorporating the modifications perform their functions at the early stage of large subunit ribosome assembly. Alternatively, the modifications significantly missing from the 27S intermediate indicate that the enzymes incorporating these modifications perform their functions at the intermediate and/or late stages of large subunit ribosome assembly.