Substrate specificity of human ribonucleotide reductase from Molt-4F cells.

Investigation of solvent effect on the active site energy of Carbonic Anhydrase and Ribonucleotide Reductase

Enzymes catalyze many biological reactions. The rates of chemical reaction in the presence ofenzymes are, in some cases, accelerated more than 10 orders of magnitude relative to thecorresponding rates in solution.In this paper a comparison between optimized structures of two enzyme molecules in aspect ofenergy and dipole moment in different conditions including presence of metallic ion, without...

Hydrogen donor specificity of cobamide-dependent ribonucleotide reductase and allosteric regulation of substrate specificity.

3.3-Å resolution cryo-EM structure of human ribonucleotide reductase with substrate and allosteric regulators bound

Ribonucleotide reductases (RNRs) convert ribonucleotides into deoxyribonucleotides, a reaction essential for DNA replication and repair. Human RNR requires two subunits for activity, the α subunit contains the active site, and the β subunit houses the radical cofactor. Here, we present a 3.3-Å resolution structure by cryo-electron microscopy (EM) of a dATP-inhibited state of human RNR. This str...

Molecular basis for allosteric specificity regulation in class Ia ribonucleotide reductase from Escherichia coli

Ribonucleotide reductase (RNR) converts ribonucleotides to deoxyribonucleotides, a reaction that is essential for DNA biosynthesis and repair. This enzyme is responsible for reducing all four ribonucleotide substrates, with specificity regulated by the binding of an effector to a distal allosteric site. In all characterized RNRs, the binding of effector dATP alters the active site to select for...

Structures of eukaryotic ribonucleotide reductase I provide insights into dNTP regulation.

Ribonucleotide reductase catalyzes a crucial step in de novo DNA synthesis and is allosterically controlled by relative levels of dNTPs to maintain a balanced pool of deoxynucleoside triphosphates in the cell. In eukaryotes, the enzyme comprises a heterooligomer of alpha(2) and beta(2) subunits. The alpha subunit, Rnr1, contains catalytic and regulatory sites. Here, we report the only x-ray str...