Reaction: 2 S-adenosyl-L-methionine + adenine2503 in 23S rRNA = S-adenosyl-L-homocysteine + L-methionine + 5'-deoxyadenosine + 2-methyladenine2503 in 23S rRNA
Other name(s): RlmN; YfgB; Cfr
Systematic name: S-adenosyl-L-methionine:23S rRNA (adenine2503-C2)-methyltransferase
Comments: Contains an [4Fe-4S] cluster [2]. 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. RlmN is an endogenous enzyme used by the cell to refine functions of the ribosome in protein synthesis [2]. The enzyme methylates adenosine by a radical mechanism with CH2 from the S-adenosyl-L-methionine and retention of the hydrogen at C-2 of adenosine2503 of 23S rRNA. It will also methylate 8-methyladenosine2503 of 23S rRNA. cf. EC 2.1.1.224 [23S rRNA (adenine2503-C8)-methyltransferase].
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:
References:
1. Toh, S.M., Xiong, L., Bae, T. and Mankin, A.S. The methyltransferase YfgB/RlmN is responsible for modification of adenosine 2503 in 23S rRNA. RNA 14 (2008) 98-106. [PMID: 18025251]
2. 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]
3. 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]
4. 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]
5. 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]