IUBMB Enzyme Nomenclature


Accepted name: [ribosomal protein uS12] (aspartate89-C3)-methylthiotransferase

Reaction: L-aspartate89-[ribosomal protein uS12] + sulfur-(sulfur carrier) + 2 S-adenosyl-L-methionine + reduced acceptor = 3-(methylsulfanyl)-L-aspartate89-[ribosomal protein uS12] + S-adenosyl-L-homocysteine + (sulfur carrier) + L-methionine + 5'-deoxyadenosine + oxidized acceptor (overall reaction)
(1a) S-adenosyl-L-methionine + L-aspartate89-[ribosomal protein uS12] + sulfur-(sulfur carrier) = S-adenosyl-L-homocysteine + L-aspartate89-[ribosomal protein uS12]-methanethiol + (sulfur carrier)
(1b) L-aspartate89-[ribosomal protein uS12]-methanethiol + S-adenosyl-L-methionine + reduced acceptor = 3-(methylsulfanyl)-L-aspartate89-[ribosomal protein uS12] + L-methionine + 5'-deoxyadenosine + oxidized acceptor

Other name(s): RimO; [ribosomal protein S12]-Asp89:sulfur-(sulfur carrier),S-adenosyl-L-methionine C3-methylthiotransferase; [ribosomal protein S12]-L-aspartate89:sulfur-(sulfur carrier),S-adenosyl-L-methionine C3-methylthiotransferase

Systematic name: [ribosomal protein uS12]-L-aspartate89:sulfur-(sulfur carrier),S-adenosyl-L-methionine C3-(methylsulfanyl)transferase

Comments: This bacterial enzyme binds two [4Fe-4S] clusters [2,3]. A bridge of five sulfur atoms is formed between the free Fe atoms of the two [4Fe-4S] clusters [6]. In the first reaction the enzyme transfers a methyl group from AdoMet to the external sulfur ion of the sulfur bridge. In the second reaction the enzyme catalyses the reductive fragmentation of a second molecule of AdoMet, yielding a 5'-deoxyadenosine radical, which then attacks the methylated sulfur atom of the polysulfide bridge, resulting in the transfer of a methylsulfanyl group to aspartate89 [5,6]. The enzyme is a member of the superfamily of S-adenosyl-L-methionine-dependent radical (radical AdoMet) enzymes.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:


1. Anton, B.P., Saleh, L., Benner, J.S., Raleigh, E.A., Kasif, S. and Roberts, R.J. RimO, a MiaB-like enzyme, methylthiolates the universally conserved Asp88 residue of ribosomal protein S12 in Escherichia coli. Proc. Natl. Acad. Sci. USA 105 (2008) 1826-1831. [PMID: 18252828]

2. Lee, K.H., Saleh, L., Anton, B.P., Madinger, C.L., Benner, J.S., Iwig, D.F., Roberts, R.J., Krebs, C. and Booker, S.J. Characterization of RimO, a new member of the methylthiotransferase subclass of the radical SAM superfamily. Biochemistry 48 (2009) 10162-10174. [PMID: 19736993]

3. Arragain, S., Garcia-Serres, R., Blondin, G., Douki, T., Clemancey, M., Latour, J.M., Forouhar, F., Neely, H., Montelione, G.T., Hunt, J.F., Mulliez, E., Fontecave, M. and Atta, M. Post-translational modification of ribosomal proteins: structural and functional characterization of RimO from Thermotoga maritima, a radical S-adenosylmethionine methylthiotransferase. J. Biol. Chem. 285 (2010) 5792-5801. [PMID: 20007320]

4. Strader, M.B., Costantino, N., Elkins, C.A., Chen, C.Y., Patel, I., Makusky, A.J., Choy, J.S., Court, D.L., Markey, S.P. and Kowalak, J.A. A proteomic and transcriptomic approach reveals new insight into β-methylthiolation of Escherichia coli ribosomal protein S12. Mol. Cell. Proteomics 10 (2011) M110.005199. [PMID: 21169565]

5. Landgraf, B.J., Arcinas, A.J., Lee, K.H. and Booker, S.J. Identification of an intermediate methyl carrier in the radical S-adenosylmethionine methylthiotransferases RimO and MiaB. J. Am. Chem. Soc. 135 (2013) 15404-15416. [PMID: 23991893]

6. Forouhar, F., Arragain, S., Atta, M., Gambarelli, S., Mouesca, J.M., Hussain, M., Xiao, R., Kieffer-Jaquinod, S., Seetharaman, J., Acton, T.B., Montelione, G.T., Mulliez, E., Hunt, J.F. and Fontecave, M. Two Fe-S clusters catalyze sulfur insertion by radical-SAM methylthiotransferases. Nat. Chem. Biol. 9 (2013) 333-338. [PMID: 23542644]

[EC created 2014, modified 2014, modified 2023]

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