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Showing 1 to 20 of 45 for “"Ribonucleotide Reductase"”.
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Investigations of the inhibition mechanisms of human ribonucleotide reductase by gemcitabine-5'-diphosphate and saccharomyces cerevisiae ribonucleotide reductase by Sml1
Ribonucleotide reductases (RNRs) catalyze the conversion of nucleotides to deoxynucleotides supplying the dNTPs required for DNA replication and DNA repair. Class I RNRs require two subunits ([alpha] and [beta]) for activity. The [alpha] subunit binds the substrates and the allosteric effectors …
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Ribonucleotide Reductase Subunit Switching in Hepatoblastoma Drug Response and Relapse
… samples revealed a significant upregulation of ribonucleotide reductase (RNR) subunit M2 (RRM2) in high-risk HB. RNR is the sole enzymatic complex in mammal cells that converts ribonucleotides to deoxyribonucleotides and plays a critical role in regulating cell division and DNA repair. We found …
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Proton-coupled electron transfer in the Escherichia coli ribonucleotide reductase
Ribonucleotide reductases (RNRs) comprise a biologically indispensable enzyme class which converts the four common nucleotides to their corresponding deoxynucleotides via a thiyl radical hydrogen abstraction mechanism. As this is the only cellular pathway for production of the monomeric precursors …
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Structural and biochemical investigations into the Neisseria gonorrhoeae ribonucleotide reductase
Ribonucleotide reductase (RNR) is the only known enzyme that converts ribonucleotide substrates to their deoxyribonucleotide products necessary for DNA synthesis and repair. For class Ia RNRs, this chemically-difficult process is tightly regulated at many levels including through allosteric …
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Regulation of the ribonucleotide reductase small subunit gene in Dictyostelium discoideum
Ribonucleotide reductase catalyzes the reduction of ribonucleotides to deoxyribonucleotides, providing precursors for the synthesis of DNA. Expression of ribonucleotide reductase is correlated with DNA synthesis: it is up-regulated during the DNA synthesis phase of the cell cycle and in the course …
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Kinetics and dynamics controlling proton-coupled electron transfer in ribonucleotide reductase
… in nature. In catalyzing the conversion of ribonucleotides to deoxyribonucleotides, ribonucleotide reductase (RNR) performs reversible, long-range PCET over a pathway of redox active amino acids ([beta]-Y₁₂₂ >/< [beta]-Y₃₅₆ >/< [alpha]-Y₇₃₁ >/< [alpha]-Y₇₃₀ >/< [alpha]-C₄₃₉) that spans ~35 Å …
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Mechanistic studies of the Class I ribonucleotide reductase from Escherichia coli
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 found in many bacteria, DNA viruses, and all eukaryotes including humans, and are composed of two homodimeric …
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Photochemical ribonucleotide reductase for the study of proton-coupled electron transfer
… generation, both in solution and within the ribonucleotide reductase enzyme. Enzymatic acitivity of class I E. coli ribonucleotide reductase requires the transport of charge from an assembled diiron-tyrosyl radical cofactor to the enzyme active site over 35 A away via an amino acid radical …
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Ribonucleotide reductase in dividing cells: Purification and inhibition studies with 4-hydroxynonenal
… of NEM (5-10 mM) enhanced the MDA formation. 2). Ribonucleotide reductase was partially purified from juvenile normal rat liver. The enzyme was purified 30 fold after DEAE-cellulose chromatography. The CDP reductase activity in tissues with different growth states or rates was compared. The enzyme …
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PHYSICOCHEMICAL STUDIES ON THE CATALYTIC AND REGULATORY SUBUNITS OF RIBONUCLEOTIDE REDUCTASE FROM CALF THYMUS
… (M1) subunits of calf thymus ribnucleotide reductase have been purified to homogeneity. Each runs as a single band in SDS-polyacrylamide gel electrophoresis with polypeptide molecular weights of 84,000 for M1 and 58,000 for M2. Additional evidence for homogeneity was obtained using high …
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Photoinitiated proton-coupled electron transfer and radical transport kinetics in class la ribonucleotide reductase
… and enzymatic substrate activation. Ribonucleotide reductases (RNRs) rely on PCET to mediate the rate-limiting step in the synthesis of DNA precursors. E. coli class Ia RNR consists of two dimeric subunits: [alpha]₂ contains the active site, while [beta]₂ contains a stable …
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Mechanism of biosynthesis of the dimanganese-tyrosyl radical cofactor of class lb Ribonucleotide reductase
Ribonucleotide reductases (RNRs) catalyze the reduction of nucleotides to deoxynucleotides in all organisms. The class Ia and lb RNRs comprise two subunits: a2 contains the site of nucleotide reduction, and p2 contains an essential stable tyrosyl radical (Y·), generated by oxidation of a dinuclear …
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Structural studies of allosteric regulation in the class Ia Ribonucleotide reductase from Escherichia coli
Ribonucleotide reductase (RNR) converts ribonucleotides to deoxyribonucleotides, the building blocks for DNA replication and repair. The E. coli class Ia enzyme requires two subunits to catalyze the radical-based reduction reaction. [beta]2 houses a diferric-tyrosyl radical cofactor and [alpha]2 …
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Cloning, sequencing, expression, and characterization of the adenosylcobalamin-dependent ribonucleotide reductase from Lactobacillus leichmannii
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1994.
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Mechanistic studies of the radical transport pathway in aminotyrosine-substituted class Ia ribonucleotide reductase
Ribonucleotide reductase (RNR) catalyzes the reduction of nucleotides to 2'- deoxynucleotides. The focus of this thesis is the F coli class la RNR, which is comprised of two homodimeric subunits, [alpha]2 and [beta]2, forming an active [alpha]2[beta]2 complex. The [beta]2 subunit harbors the stable …
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Mechanistic investigations of the radical initiation pathway of class I ribonucleotide reductase from Escherichia coli
Ribonucleotide reductases (RNR) catalyze the conversion of nucleoside diphosphates to deoxynucleoside diphosphates, an essential step in DNA replication and repair. The Class I enzyme from Escherichia coli is composed of two subunits: R1 and R2. R contains the active site for nucleotide reduction …
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Mechanism of assembly of the tyrosyl radical-diiron(III) cofactor of E. coli ribonucleotide reductase
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1996.
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Defining the active form of ribonucleotide reductase from Saccharomyces cerevisiae in vitro and in vivo
Ribonucleotide reductase (RNR) catalyzes the conversion of ribonucleotides to deoxyribonucleotides. Saccharomyces cerevisiae RNR is a class I RNR composed of a dimeric large subunit (RI), containing the active site and allosteric effector sites, and a dimeric small subunit (R2) which houses the …
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cDNA Cloning and Gene Characterization of Large and Small Subunits of Ribonucleotide Reductase in Soybean
Ribonucleotide reductase (RNR) reduces four ribonucleoside diphosphates to corresponding deoxyribonucleoside diphosphates, which are transformed into deoxyribonucleoside triphosphates, substrates for DNA polymerase. By controlling the supply and balance of deoxyribonucleoside diphosphates, RNR …
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Mechanistic studies of proton-coupled electron transfer in aminotyrosine- and fluorotyrosine- substituted class Ia Ribonucleotide reductase
Ribonucleotide reductase (RNR) catalyzes the conversion of nucleotides to 2'- deoxynucleotides in all organisms. The class Ia RNR from Escherichia coli is active as an a2p2 complex and utilizes an unprecedented mechanism of reversible proton-coupled electron transfer (PCET) to propagate a stable …
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