5D1Y

Low resolution crystal structure of human ribonucleotide reductase alpha6 hexamer in complex with dATP

5D1Y の概要

• エントリーDOI: 10.2210/pdb5d1y/pdb
• 分子名称: Ribonucleoside-diphosphate reductase large subunit (1 entity in total)
• 機能のキーワード: deoxyribonucleotide, oligomerization, atp cone, oxidoreductase
• 由来する生物種: Homo sapiens (Human)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 184700.78

構造登録者

Ando, N.,Li, H.,Brignole, E.J.,Thompson, S.,McLaughlin, M.I.,Page, J.,Asturias, F.,Stubbe, J.,Drennan, C.L. (登録日: 2015-08-04, 公開日: 2016-01-20, 最終更新日: 2024-10-09)

主引用文献

Ando, N.,Li, H.,Brignole, E.J.,Thompson, S.,McLaughlin, M.I.,Page, J.E.,Asturias, F.J.,Stubbe, J.,Drennan, C.L.
Allosteric Inhibition of Human Ribonucleotide Reductase by dATP Entails the Stabilization of a Hexamer.
Biochemistry, 55:373-381, 2016

PubMed Abstract: Ribonucleotide reductases (RNRs) are responsible for all de novo biosynthesis of DNA precursors in nature by catalyzing the conversion of ribonucleotides to deoxyribonucleotides. Because of its essential role in cell division, human RNR is a target for a number of anticancer drugs in clinical use. Like other class Ia RNRs, human RNR requires both a radical-generation subunit (β) and nucleotide-binding subunit (α) for activity. Because of their complex dependence on allosteric effectors, however, the active and inactive quaternary forms of many class Ia RNRs have remained in question. Here, we present an X-ray crystal structure of the human α subunit in the presence of inhibiting levels of dATP, depicting a ring-shaped hexamer (α6) where the active sites line the inner hole. Surprisingly, our small-angle X-ray scattering (SAXS) results indicate that human α forms a similar hexamer in the presence of ATP, an activating effector. In both cases, α6 is assembled from dimers (α2) without a previously proposed tetramer intermediate (α4). However, we show with SAXS and electron microscopy that at millimolar ATP, the ATP-induced α6 can further interconvert with higher-order filaments. Differences in the dATP- and ATP-induced α6 were further examined by SAXS in the presence of the β subunit and by activity assays as a function of ATP or dATP. Together, these results suggest that dATP-induced α6 is more stable than the ATP-induced α6 and that stabilization of this ring-shaped configuration provides a mechanism to prevent access of the β subunit to the active site of α.

PubMed: 26727048
DOI: 10.1021/acs.biochem.5b01207

実験手法

X-RAY DIFFRACTION (9.005 Å)