ジャーナル: Cell / 年: 2018 タイトル: Helicase-Dependent RNA Decay Illuminated by a Cryo-EM Structure of a Human Nuclear RNA Exosome-MTR4 Complex. 著者: Eva-Maria Weick / M Rhyan Puno / Kurt Januszyk / John C Zinder / Michael A DiMattia / Christopher D Lima / 要旨: The ribonucleolytic RNA exosome interacts with RNA helicases to degrade RNA. To understand how the 3' to 5' Mtr4 helicase engages RNA and the nuclear exosome, we reconstituted 14-subunit Mtr4- ...The ribonucleolytic RNA exosome interacts with RNA helicases to degrade RNA. To understand how the 3' to 5' Mtr4 helicase engages RNA and the nuclear exosome, we reconstituted 14-subunit Mtr4-containing RNA exosomes from Saccharomyces cerevisiae, Schizosaccharomyces pombe, and human and show that they unwind structured substrates to promote degradation. We loaded a human exosome with an optimized DNA-RNA chimera that stalls MTR4 during unwinding and determined its structure to an overall resolution of 3.45 Å by cryoelectron microscopy (cryo-EM). The structure reveals an RNA-engaged helicase atop the non-catalytic core, with RNA captured within the central channel and DIS3 exoribonuclease active site. MPP6 tethers MTR4 to the exosome through contacts to the RecA domains of MTR4. EXOSC10 remains bound to the core, but its catalytic module and cofactor C1D are displaced by RNA-engaged MTR4. Competition for the exosome core may ensure that RNA is committed to degradation by DIS3 when engaged by MTR4.
ダウンロード / ファイル: emd_7812.map.gz / 形式: CCP4 / 大きさ: 216 MB / タイプ: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES)
注釈
Human nuclear exosome-MTR4 RNA complex - composite map after focused reconstruction
ボクセルのサイズ
X=Y=Z: 1.07 Å
密度
表面レベル
登録者による: 0.03 / ムービー #1: 0.03
最小 - 最大
-0.120548755 - 0.19239767
平均 (標準偏差)
0.00004187069 (±0.0019666187)
対称性
空間群: 1
詳細
EMDB XML:
マップ形状
Axis order
Z
X
Y
Origin
0
0
0
サイズ
384
384
384
Spacing
384
384
384
セル
A=B=C: 410.88 Å α=β=γ: 90.0 °
CCP4マップ ヘッダ情報:
mode
Image stored as Reals
Å/pix. X/Y/Z
1.07
1.07
1.07
M x/y/z
384
384
384
origin x/y/z
0.000
0.000
0.000
length x/y/z
410.880
410.880
410.880
α/β/γ
90.000
90.000
90.000
start NX/NY/NZ
0
0
0
NX/NY/NZ
384
384
384
MAP C/R/S
3
1
2
start NC/NR/NS
0
0
0
NC/NR/NS
384
384
384
D min/max/mean
-0.121
0.192
0.000
-
添付データ
-
試料の構成要素
-
全体 : Human nuclear exosome-MTR4 helicase captured after unwinding a DN...
全体
名称: Human nuclear exosome-MTR4 helicase captured after unwinding a DNA/RNA substrate
要素
複合体: Human nuclear exosome-MTR4 helicase captured after unwinding a DNA/RNA substrate
-
超分子 #1: Human nuclear exosome-MTR4 helicase captured after unwinding a DN...
超分子
名称: Human nuclear exosome-MTR4 helicase captured after unwinding a DNA/RNA substrate タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: #1-#15 詳細: Human C1D/Rrp47 also in the sample, but was not observed in density
Models were rebuilt manually using Coot, with real space refinement with local scaling followed by Phenix real space refinement with suboptimal global scaling.