EC Explorer

2.8.4.4

[ribosomal protein S12] (aspartate⁸⁹-C³)-methylthiotransferase

L-aspartate⁸⁹-[ribosomal protein S12] + sulfur-(sulfur carrier) + 2 S-adenosyl-L-methionine + reduced acceptor = 3-(methylsulfanyl)-L-aspartate⁸⁹-[ribosomal protein S12] + S-adenosyl-L-homocysteine + (sulfur carrier) + L-methionine + 5′-deoxyadenosine + oxidized acceptor (overall reaction);; (1a) S-adenosyl-L-methionine + L-aspartate⁸⁹-[ribosomal protein S12] + sulfur-(sulfur carrier) = S-adenosyl-L-homocysteine + L-aspartate⁸⁹-[ribosomal protein S12]-methanethiol + (sulfur carrier);; (1b) L-aspartate⁸⁹-[ribosomal protein S12]-methanethiol + S-adenosyl-L-methionine + reduced acceptor = 3-(methylsulfanyl)-L-aspartate⁸⁹-[ribosomal protein S12] + L-methionine + 5′-deoxyadenosine + oxidized acceptor

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

[ribosomal protein S12]-L-aspartate⁸⁹:sulfur-(sulfur carrier),S-adenosyl-L-methionine C³-(methylsulfanyl)transferase

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.

created 2014, modified 2014