The multi-site specific RluC catalyzes isomerization of uridines to pseudouridines at positions 955 (in hairpin 39 of Domain II), 2504 (in single stranded region between hairpins 89-90 of Domain V in Peptidyl Transferase Center) and 2580 (in stem of helix 90 of the same Domain V) in 23S rRNA. In vitro transcript of 23S ribosomal RNA was used as substrate. RluC possess a N-terminal S4 RNA binding domain. Proteolytically derived fragment of the enzyme consisting of residues 89-319 has been crystallized and shown to retain catalytic activity. RluC belongs to the same subgroup of RNA pseudourodine synthases as RluA, RluD, TruC, Pus5, Pus6, Pus8 and Pus9.