Ribosomal RNA small subunit methyltransferase I (RsmI), also known as rRNA (cytidine-2'-O-)-methyltransferase
RsmI is an S-AdoMet (S-adenosyl-L-methionine or SAM)-dependent methyltransferase responsible for the 2'-O-methylation of cytidine 1402 (C1402) at the P site of bacterial 16S rRNA. Another S-AdoMet-dependent methyltransferase, RsmH (not included in this family), is responsible for N4-methylation at C1402. These methylation reactions may occur at a late step during 30S assembly in the cell. The dimethyl modification is believed to be conserved in bacteria, may play a role in fine-tuning the shape and functions of the P-site to increase the translation fidelity, and has been shown for Staphylococcus aureus, to contribute to virulence in host animals by conferring resistance to oxidative stress.