Transferases;
Transferring sulfur-containing groups;
Sulfurtransferases
BRITE hierarchy

dethiobiotin:sulfur-(sulfur carrier) sulfurtransferase

dethiobiotin + sulfur-(sulfur carrier) + 2 S-adenosyl-L-methionine + 2 reduced [2Fe-2S] ferredoxin = biotin + (sulfur carrier) + 2 L-methionine + 2 5'-deoxyadenosine + 2 oxidized [2Fe-2S] ferredoxin [RN:R01078]

R01078
Reaction

dethiobiotin [CPD:C01909];
sulfur-(sulfur carrier);
S-adenosyl-L-methionine [CPD:C00019];
reduced [2Fe-2S] ferredoxin [CPD:C22150]

The enzyme binds a [4Fe-4S] and a [2Fe-2S] cluster. In every reaction cycle, the enzyme consumes two molecules of AdoMet. The first reaction produces 5'-deoxyadenosine and 4,5-secobiotin. Reaction with another equivalent of AdoMet results in abstraction of the C-6 methylene pro-S hydrogen atom from 4,5-secobiotin, and the resulting carbon radical is quenched via formation of an intramolecular C-S bond, thus closing the biotin tetrahydrothiophene ring. The sulfur donor is believed to be the [2Fe-2S] cluster, which is sacrificed in the process, so that in vitro the reaction is a single turnover. In vivo, the [2Fe-2S] cluster can be reassembled by the Isc or Suf iron-sulfur cluster assembly systems, to allow further catalysis.

EC 2.8.1.6 created 1999, modified 2006, modified 2011, modified 2014