Iron and Free Radical in Ribonucleotide Reductase
نویسندگان
چکیده
منابع مشابه
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...
متن کاملCharacterization of the free radical of mammalian ribonucleotide reductase.
Mouse fibroblast 3T6 cells, selected for resistance to hydroxyurea, were shown to overproduce protein M2, one of the two nonidentical subunits of mammalian ribonucleotide reductase. Packed resistant cells gave an EPR signal at 77 K very much resembling the signal given by the tyrosine-free radical of the B2 subunit of Escherichia coli ribonucleotide reductase. Also, the M2-specific free radical...
متن کاملAn 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...
متن کاملTyrosyl free radical formation in the small subunit of mouse ribonucleotide reductase.
Each R2 subunit of mammalian ribonucleotide reductase contains a pair of high spin ferric ions and a tyrosyl free radical essential for activity. To study the mechanism of tyrosyl radical formation, substoichiometric amounts of Fe(II) were added to recombinant mouse R2 apoprotein under strictly anaerobic conditions and then the solution was exposed to air. Low temperature EPR spectroscopy showe...
متن کاملSpectroscopic Studies of the Iron and Manganese Reconstituted Tyrosyl Radical in Bacillus Cereus Ribonucleotide Reductase R2 Protein
Ribonucleotide reductase (RNR) catalyzes the rate limiting step in DNA synthesis where ribonucleotides are reduced to the corresponding deoxyribonucleotides. Class Ib RNRs consist of two homodimeric subunits: R1E, which houses the active site; and R2F, which contains a metallo cofactor and a tyrosyl radical that initiates the ribonucleotide reduction reaction. We studied the R2F subunit of B. c...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1973
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(19)43313-9