Reaction: 2 S-adenosyl-L-methionine + adenine2503 in 23S rRNA = S-adenosyl-L-homocysteine + L-methionine + 5'-deoxyadenosine + 8-methyladenine2503 in 23S rRNA
Other name(s): Cfr (gene name)
Systematic name: S-adenosyl-L-methionine:23S rRNA (adenine2503-C8)-methyltransferase
Comments: This enzyme is a member of the 'AdoMet radical' (radical SAM) family. S-adenosyl-L-methionine acts as both a radical generator and as the source of the appended methyl group. It contains an [4Fe-S] cluster [1]. Cfr is an plasmid-acquired methyltransferase that protects cells from the action of antibiotics [1]. The enzyme methylates adenosine at position 2503 of 23S rRNA by a radical mechanism, transferring a CH2 group from S-adenosyl-L-methionine while retaining the hydrogen at the C-8 position of the adenine. It will also methylate 2-methyladenine produced by the action of EC 2.1.1.192 [23S rRNA (adenine2503-C2)-methyltransferase].
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Giessing, A.M., Jensen, S.S., Rasmussen, A., Hansen, L.H., Gondela, A., Long, K., Vester, B. and Kirpekar, F. Identification of 8-methyladenosine as the modification catalyzed by the radical SAM methyltransferase Cfr that confers antibiotic resistance in bacteria. RNA 15 (2009) 327-336. [PMID: 19144912]
2. Kaminska, K.H., Purta, E., Hansen, L.H., Bujnicki, J.M., Vester, B. and Long, K.S. Insights into the structure, function and evolution of the radical-SAM 23S rRNA methyltransferase Cfr that confers antibiotic resistance in bacteria. Nucleic Acids Res. 38 (2010) 1652-1663. [PMID: 20007606]
3. Yan, F., LaMarre, J.M., Ršhrich, R., Wiesner, J., Jomaa, H., Mankin, A.S., Fujimori, D.G. RlmN and Cfr are radical SAM enzymes involved in methylation of ribosomal RNA. J. Am. Chem. Soc. 132 (2010) 3953-3964. [PMID: 20184321]
4. Yan, F. and Fujimori, D.G. RNA methylation by Radical SAM enzymes RlmN and Cfr proceeds via methylene transfer and hydride shift. Proc. Natl. Acad. Sci. USA 108 (2011) 3930-3934. [PMID: 21368151]
5. Grove, T.L., Benner, J.S., Radle, M.I., Ahlum, J.H., Landgraf, B.J., Krebs, C. and Booker, S.J. A radically different mechanism for S-adenosylmethionine-dependent methyltransferases. Science 332 (2011) 604-607. [PMID: 21415317]
6. Boal, A.K., Grove, T.L., McLaughlin, M.I., Yennawar, N.H., Booker, S.J. and Rosenzweig, A.C. Structural basis for methyl transfer by a radical SAM enzyme. Science 332 (2011) 544-545. [PMID: 21527678]