ジャーナル: Nat Struct Mol Biol / 年: 2011 タイトル: Structural basis for allosteric regulation of human ribonucleotide reductase by nucleotide-induced oligomerization. 著者: James Wesley Fairman / Sanath Ranjan Wijerathna / Md Faiz Ahmad / Hai Xu / Ryo Nakano / Shalini Jha / Jay Prendergast / R Martin Welin / Susanne Flodin / Annette Roos / Pär Nordlund / Zongli ...著者: James Wesley Fairman / Sanath Ranjan Wijerathna / Md Faiz Ahmad / Hai Xu / Ryo Nakano / Shalini Jha / Jay Prendergast / R Martin Welin / Susanne Flodin / Annette Roos / Pär Nordlund / Zongli Li / Thomas Walz / Chris Godfrey Dealwis / 要旨: Ribonucleotide reductase (RR) is an α(n)β(n) (RR1-RR2) complex that maintains balanced dNTP pools by reducing NDPs to dNDPs. RR1 is the catalytic subunit, and RR2 houses the free radical required ...Ribonucleotide reductase (RR) is an α(n)β(n) (RR1-RR2) complex that maintains balanced dNTP pools by reducing NDPs to dNDPs. RR1 is the catalytic subunit, and RR2 houses the free radical required for catalysis. RR is allosterically regulated by its activator ATP and its inhibitor dATP, which regulate RR activity by inducing oligomerization of RR1. Here, we report the first X-ray structures of human RR1 bound to TTP alone, dATP alone, TTP-GDP, TTP-ATP, and TTP-dATP. These structures provide insights into regulation of RR by ATP or dATP. At physiological dATP concentrations, RR1 forms inactive hexamers. We determined the first X-ray structure of the RR1-dATP hexamer and used single-particle electron microscopy to visualize the α(6)-ββ'-dATP holocomplex. Site-directed mutagenesis and functional assays confirm that hexamerization is a prerequisite for inhibition by dATP. Our data indicate a mechanism for regulating RR activity by dATP-induced oligomerization.
解像度: 3.21→49.94 Å / Cor.coef. Fo:Fc: 0.957 / Cor.coef. Fo:Fc free: 0.922 / Occupancy max: 1 / Occupancy min: 1 / SU B: 46.546 / SU ML: 0.378 / 交差検証法: THROUGHOUT / ESU R Free: 0.523 / 立体化学のターゲット値: MAXIMUM LIKELIHOOD / 詳細: HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS
Rfactor
反射数
%反射
Selection details
Rfree
0.25389
1576
5.1 %
RANDOM
Rwork
0.17966
-
-
-
obs
0.18347
29455
98.13 %
-
溶媒の処理
イオンプローブ半径: 0.8 Å / 減衰半径: 0.8 Å / VDWプローブ半径: 1.2 Å / 溶媒モデル: MASK