Abstract of the PDB Structure's related Publication:
Structural, biochemical, and genetic techniques were applied to investigate the function of FtsJ, a recently identified heat shock protein. FtsJ is well conserved, from bacteria to humans. The 1.5 A crystal structure of FtsJ in complex with its cofactor S-adenosylmethionine revealed that FtsJ has a methyltransferase fold. The molecular surface of FtsJ exposes a putative nucleic acid binding groove composed of highly conserved, positively charged residues. Substrate analysis showed that FtsJ methylates 23S rRNA within 50S ribosomal subunits in vitro and in vivo. Null mutations in ftsJ show a dramatically altered ribosome profile, a severe growth disadvantage, and a temperature-sensitive phenotype. Our results reveal an unexpected link between the heat shock response and RNA metabolism.
Substrate analysis showed that RlmE (formerly FtsJ, RrmJ) methylates the 2′-O ribose of the universally conserved U2552 in the so-called A-loop (hairpin 92) of the Peptidyl Transferase Center (domain V) of 23S rRNA. E. coli RlmE is active only on the ribosome and the 50 S ribosomal subunit, but is inactive on free rRNA. AdoMet is the methyl group donor. The enzyme possess a TRAM domain. The homologous S.cerevisiae mitochondrial enzyme is Mrm2. In cytoplasmic large subunit rRNA, the equivalent Um2921 (2552 in E. coli numbering) is catalyzed by C/D box RNP, using snR52 as guide-RNA.