Transferases;
Transferring sulfur-containing groups;
Transferring alkylthio groups
BRITE hierarchy

tRNA N6-(3-methylbut-2-en-1-yl)-adenine37:[3Fe-4S] iron-sulfur cluster,S-adenosyl-L-methionine C2-(methylsulfanyl)transferase

N6-(3-methylbut-2-en-1-yl)-adenine37 in tRNA + a [3Fe-4S] iron-sulfur cluster + 2 S-adenosyl-L-methionine + reduced electron acceptor = N6-(3-methylbut-2-en-1-yl)-2-(methylsulfanyl)adenine37 in tRNA + S-adenosyl-L-homocysteine + a [3Fe-3S] iron-sulfur cluster + L-methionine + 5'-deoxyadenine + electron acceptor

N6-(3-methylbut-2-en-1-yl)-adenine37 in tRNA;
[3Fe-4S] iron-sulfur cluster;
S-adenosyl-L-methionine [CPD:C00019];
reduced electron acceptor

The enzyme is a member of the AdoMet radical (radical SAM) family. It contains one [4Fe-4S] cluster (the main cluster) and one [3Fe-4S] cluster (the auxiliary cluster). The reaction is thought to take place in two steps. In the first step, one molecule of SAM is used to methylate a bridging mu-sulfido ion of the auxiliary cluster, forming a thio-methyl group. In the second step, a second SAM molecule is cleaved to a 5'-deoxyadenosyl 5'-radical, which abstracts the C2 hydrogen of the substrate, and the thio-methyl group is transferred from the auxiliary cluster to the radical-activated carbon in the tRNA substrate. The auxiliary cluster is left in an inactive [3Fe-3S] state and must be repaired or replaced before the enzyme could catalyse the next round.

EC 2.8.4.3 created 2014, modified 2015, modified 2026