A substrate radical intermediate in the reaction between ribonucleotide reductase from Escherichia coli and 2'-azido-2'-deoxynucleoside diphosphates.
نویسندگان
چکیده
منابع مشابه
A substrate radical intermediate in the reaction between ribonucleotide reductase from Escherichia coli and 2'-azido-2'-deoxynucleoside diphosphates.
The B2 subunit of ribonucleotide reductase from Escherichia coli contains a tyrosine radical which is essential for enzyme activity. In the reaction between ribonucleotide reductase and the substrate analogue 2'-azido-2'-deoxycytidine 5'-diphosphate a new transient radical is formed. The EPR characteristics of this new radical species are consistent with a localization of the unpaired electron ...
متن کاملInteractions of 2'-modified azido- and haloanalogs of deoxycytidine 5'-triphosphate with the anaerobic ribonucleotide reductase of Escherichia coli.
The anaerobic Escherichia coli ribonucleotide reductase (class III reductase) responsible for the synthesis of the deoxyribonucleotides required for anaerobic DNA replication contains an oxygen-sensitive glycyl radical (Gly-681) suggesting involvement of radical chemistry in catalysis. The amino acid sequence of this enzyme completely differs from that of earlier described aerobic class I (prot...
متن کاملEPR distance measurements support a model for long-range radical initiation in E. coli ribonucleotide reductase.
The class I E. coli ribonucleotide reductase, composed of homodimers of R1 and R2, catalyzes the conversion of nucleoside diphosphates to deoxynucleoside diphosphates. The reduction process involves the tyrosyl radical on R2 that generates a transient thiyl radical on R1 over a proposed distance of 35 A. A mechanism-based inhibitor, 2'-azido-2'-deoxyuridine-5'-diphosphate, that reduces the tyro...
متن کاملStructure of the nitrogen-centered radical formed during inactivation of E. coli ribonucleotide reductase by 2'-azido-2'-deoxyuridine-5'-diphosphate: trapping of the 3'-ketonucleotide.
Ribonucleotide reductases (RNRs) catalyze the conversion of nucleotides to deoxynucleotides providing the monomeric precursors required for DNA replication and repair. The class I RNRs are composed of two homodimeric subunits: R1 and R2. R1 has the active site where nucleotide reduction occurs, and R2 contains the diiron tyrosyl radical (Y*) cofactor essential for radical initiation on R1. Mech...
متن کاملActive site of ribonucleoside diphosphate reductase from Escherichia coli. Inactivation of the enzyme by 2'-substituted ribonucleoside diphosphates.
Ribonucleoside diphosphate reductase is an allosteric enzyme consisting of two nonidentical subunits, proteins B1 and B2. B1 contains dithiols which participate in the oxidation-reduction reactions of electron transport, while B2 contains a free radical essential for activity. Ribonucleoside diphosphates are bound to B1 but not to B2. Addition of 2'-deoxy-2'-chloro ribonucleoside diphosphates t...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1983
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(20)82027-4