ジャーナル: Nature / 年: 2015 タイトル: Structure of mammalian eIF3 in the context of the 43S preinitiation complex. 著者: Amedee des Georges / Vidya Dhote / Lauriane Kuhn / Christopher U T Hellen / Tatyana V Pestova / Joachim Frank / Yaser Hashem / 要旨: During eukaryotic translation initiation, 43S complexes, comprising a 40S ribosomal subunit, initiator transfer RNA and initiation factors (eIF) 2, 3, 1 and 1A, attach to the 5'-terminal region of ...During eukaryotic translation initiation, 43S complexes, comprising a 40S ribosomal subunit, initiator transfer RNA and initiation factors (eIF) 2, 3, 1 and 1A, attach to the 5'-terminal region of messenger RNA and scan along it to the initiation codon. Scanning on structured mRNAs also requires the DExH-box protein DHX29. Mammalian eIF3 contains 13 subunits and participates in nearly all steps of translation initiation. Eight subunits having PCI (proteasome, COP9 signalosome, eIF3) or MPN (Mpr1, Pad1, amino-terminal) domains constitute the structural core of eIF3, to which five peripheral subunits are flexibly linked. Here we present a cryo-electron microscopy structure of eIF3 in the context of the DHX29-bound 43S complex, showing the PCI/MPN core at ∼6 Å resolution. It reveals the organization of the individual subunits and their interactions with components of the 43S complex. We were able to build near-complete polyalanine-level models of the eIF3 PCI/MPN core and of two peripheral subunits. The implications for understanding mRNA ribosomal attachment and scanning are discussed.
ダウンロード / ファイル: emd_3056.map.gz / 形式: CCP4 / 大きさ: 100.6 MB / タイプ: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES)
注釈
Reconstruction of eIF3 octamer core
ボクセルのサイズ
X=Y=Z: 1.66 Å
密度
表面レベル
登録者による: 0.025 / ムービー #1: 0.025
最小 - 最大
-0.06188392 - 0.12141231
平均 (標準偏差)
0.00010273 (±0.00224358)
対称性
空間群: 1
詳細
EMDB XML:
マップ形状
Axis order
X
Y
Z
Origin
0
0
0
サイズ
300
300
300
Spacing
300
300
300
セル
A=B=C: 498.0 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
1.66
1.66
1.66
M x/y/z
300
300
300
origin x/y/z
0.000
0.000
0.000
length x/y/z
498.000
498.000
498.000
α/β/γ
90.000
90.000
90.000
start NX/NY/NZ
-80
0
-4
NX/NY/NZ
161
13
58
MAP C/R/S
1
2
3
start NC/NR/NS
0
0
0
NC/NR/NS
300
300
300
D min/max/mean
-0.062
0.121
0.000
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添付データ
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試料の構成要素
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全体 : eIF3 octamer core of Rabbit eIF3
全体
名称: eIF3 octamer core of Rabbit eIF3
要素
試料: eIF3 octamer core of Rabbit eIF3
複合体: 40S small ribosomal subunit
タンパク質・ペプチド: eukaryotic initiation factor 3
タンパク質・ペプチド: eukaryotic initiation factor 2
タンパク質・ペプチド: DHX29
タンパク質・ペプチド: eukaryotic initiation factor 1
タンパク質・ペプチド: eukaryotic initiation factor 1A
RNA: initiator transfer RNA
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超分子 #1000: eIF3 octamer core of Rabbit eIF3
超分子
名称: eIF3 octamer core of Rabbit eIF3 / タイプ: sample / ID: 1000 詳細: The sample was monodisperse, eIF3 octamer core was locally refined from a reconstruction of the mammalian 43S preinitiation complex 集合状態: One octamer / Number unique components: 7