Thesis presented December 20, 2002
Abstract:
Recently, iron sulfur centers have been shown as essential for the reductive cleavage of S-adenosylmethionine (AdoMet) into a 5'-deoxyadenosyl radical (Ado•). The latter has the ability to oxidize a polypeptide chain amino acid giving rise to a free radical protein. The anaerobic ribonucleotide reductase (aRNR) from Escherichai coli is a prototype of this new class of enzymes. It carries a glycyl radical formed during an activation process mediated by the concerted action of (i) an electron source, (ii) a thiol, (iii) AdoMet and (iv) an activating anzyme which contains a [4Fe-4S] cluster per polypetide chain. The electron transfer mechanisms participating in the activation process have benn studied with regard to these different components and a new proposal has been elaborated for the reductive cleavage of AdoMet.
Keywords:
FeS center, catalyse, S-adenosylmethionine, AdoMet, anaerobic ribonucleotide reductase, aRNR