RsmC catalyzes the transfer of a methyl group from S-adenosyl-l-methionine (SAM) to G1207 (E. coli numbering) in helix 34 of 16S rRNA (m2G1207). The enzyme is composed of two homologous domains tandemly duplicated within a single polypeptide. The crystal structure reveals that the orientation of target nucleotide in the active site reveals that G1207 has to disengage from its Watson-Crick base pairing interaction with C1051 in the 16 S rRNA and flip out into the active site prior to its modification. This is consistent with previous hypothesis that this enzyme recognizes a subunit assembly intermediate, not the free 16S rRNA, nor the fully mature 30S-subunit ribosome. T. thermophilus RsmC is closely related to E. coli RsmC and E. coli RsmD (m2G966/16S rRNA) as well as to other MTases from Gram-positive bacteria and Archaea, typified by the Mj0882 protein from M. jannaschii (1dus in PDB)