6aui

Publication Abstract from PubMed

Ribonucleotide reductases (RNRs) convert ribonucleotides into deoxyribonucleotides, a reaction essential for DNA replication and repair. Human RNR requires two subunits for activity, the alpha subunit contains the active site, and the beta subunit houses the radical cofactor. Here, we present a 3.3-A resolution structure by cryo-electron microscopy (EM) of a dATP-inhibited state of human RNR. This structure, which was determined in the presence of substrate CDP and allosteric regulators ATP and dATP, has three alpha2 units arranged in an alpha6 ring. At near-atomic resolution, these data provide insight into the molecular basis for CDP recognition by allosteric specificity effectors dATP/ATP. Additionally, we present lower-resolution EM structures of human alpha6 in the presence of both the anticancer drug clofarabine triphosphate and beta2. Together, these structures support a model for RNR inhibition in which beta2 is excluded from binding in a radical transfer competent position when alpha exists as a stable hexamer.

3.3-A resolution cryo-EM structure of human ribonucleotide reductase with substrate and allosteric regulators bound.,Brignole EJ, Tsai KL, Chittuluru J, Li H, Aye Y, Penczek PA, Stubbe J, Drennan CL, Asturias F Elife. 2018 Feb 20;7. pii: 31502. doi: 10.7554/eLife.31502. PMID:29460780^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.