The iron center in ribonucleotide reductase

An iron-sulfur center and a free radical in the active anaerobic ribonucleotide reductase of Escherichia coli.

Anaerobically grown Escherichia coli contain an oxygen-sensitive ribonucleotide reductase. The enzyme requires anaerobic activation by two E. coli fractions with S-adenosylmethionine, NADPH, dithiothreitol, and KCl. We now find that photochemically reduced deazaflavin can substitute for these two fractions and NADPH. The reductase contained roughly equimolar amounts of iron and sulfide, suggest...

The activating component of the anaerobic ribonucleotide reductase from Escherichia coli. An iron-sulfur center with only three cysteines.

Class III anaerobic ribonucleotide reductase small component, named protein beta, contains a (4Fe-4S) center. Its function is to mediate electron transfer from reduced flavodoxin to S-adenosylmethionine, required for the introduction of a glycyl radical in the large component, named protein alpha, which then becomes active for the reduction of ribonucleotides. By site-directed mutagenesis we de...

Ribonucleotide reductase in developing brain.

The tyrosyl free radical in ribonucleotide reductase.

The enzyme, ribonucleotide reductase, catalyses the formation of deoxyribonucleotides from ribonucleotides, a reaction essential for DNA synthesis in all living cells. The Escherichia coli ribonucleotide reductase, which is the prototype of all known eukaryotic and virus-coded enzymes, consists of two nonidentical subunits, proteins B1 and B2. The B2 subunit contains an antiferromagnetically co...

Ribonucleotide Reductase Inhibitors for Restenosis

Percutaneous transluminal coronary angioplasty (PTCA) has greatly benefited patients with occluded coronary arteries, but its benefits have been undermined by a high incidence of restenosis. The introduction of coronary stents has significantly improved the short and long term outcome but restenosis still occurs in approximately 15-30 % of patients within 6 months. Research efforts are now bein...