ジャーナル: Nat Struct Mol Biol / 年: 2011 タイトル: The structural basis for MCM2-7 helicase activation by GINS and Cdc45. 著者: Alessandro Costa / Ivar Ilves / Nele Tamberg / Tatjana Petojevic / Eva Nogales / Michael R Botchan / James M Berger / 要旨: Two central steps for initiating eukaryotic DNA replication involve loading of the Mcm2-7 helicase onto double-stranded DNA and its activation by GINS-Cdc45. To better understand these events, we ...Two central steps for initiating eukaryotic DNA replication involve loading of the Mcm2-7 helicase onto double-stranded DNA and its activation by GINS-Cdc45. To better understand these events, we determined the structures of Mcm2-7 and the CMG complex by using single-particle electron microscopy. Mcm2-7 adopts two conformations--a lock-washer-shaped spiral state and a planar, gapped-ring form--in which Mcm2 and Mcm5 flank a breach in the helicase perimeter. GINS and Cdc45 bridge this gap, forming a topologically closed assembly with a large interior channel; nucleotide binding further seals off the discontinuity between Mcm2 and Mcm5, partitioning the channel into two smaller pores. Together, our data help explain how GINS and Cdc45 activate Mcm2-7, indicate that Mcm2-7 loading may be assisted by a natural predisposition of the hexamer to form open rings, and suggest a mechanism by which the CMG complex assists DNA strand separation.
ダウンロード / ファイル: emd_1832.map.gz / 形式: CCP4 / 大きさ: 1001 KB / タイプ: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES)
注釈
Volume file of the ADP.BeF3-bound CMG complex
ボクセルのサイズ
X=Y=Z: 5.7 Å
密度
表面レベル
登録者による: 0.42 / ムービー #1: 0.42
最小 - 最大
-0.15938 - 2.05233
平均 (標準偏差)
-0.00245379 (±0.155001)
対称性
空間群: 1
詳細
EMDB XML:
マップ形状
Axis order
X
Y
Z
Origin
-32
-32
-32
サイズ
64
64
64
Spacing
64
64
64
セル
A=B=C: 364.8 Å α=β=γ: 90 °
CCP4マップ ヘッダ情報:
mode
Image stored as Reals
Å/pix. X/Y/Z
5.7
5.7
5.7
M x/y/z
64
64
64
origin x/y/z
0.000
0.000
0.000
length x/y/z
364.800
364.800
364.800
α/β/γ
90.000
90.000
90.000
start NX/NY/NZ
-30
-24
-70
NX/NY/NZ
61
49
141
MAP C/R/S
1
2
3
start NC/NR/NS
-32
-32
-32
NC/NR/NS
64
64
64
D min/max/mean
-0.159
2.052
-0.002
-
添付データ
-
試料の構成要素
+
全体 : Drosophila melanogaster CMG complex bound to ADP.BeF3
全体
名称: Drosophila melanogaster CMG complex bound to ADP.BeF3
要素
試料: Drosophila melanogaster CMG complex bound to ADP.BeF3
タンパク質・ペプチド: Mcm2ミニ染色体維持複合体成分2
タンパク質・ペプチド: Mcm3
タンパク質・ペプチド: Mcm4
タンパク質・ペプチド: Mcm5
タンパク質・ペプチド: Mcm6
タンパク質・ペプチド: Mcm7
タンパク質・ペプチド: Psf1
タンパク質・ペプチド: Psf2
タンパク質・ペプチド: Psf3
タンパク質・ペプチド: Sld5
タンパク質・ペプチド: Cdc45
+
超分子 #1000: Drosophila melanogaster CMG complex bound to ADP.BeF3
超分子
名称: Drosophila melanogaster CMG complex bound to ADP.BeF3 タイプ: sample / ID: 1000 / 詳細: The sample was monodisperse 集合状態: One Mcm2-7 heterohexamer binds to one GINS heterotetramer and a Cdc45 monomer Number unique components: 11