ジャーナル: PLoS One / 年: 2012 タイトル: Acetylcholine-binding protein in the hemolymph of the planorbid snail Biomphalaria glabrata is a pentagonal dodecahedron (60 subunits). 著者: Michael Saur / Vanessa Moeller / Katharina Kapetanopoulos / Sandra Braukmann / Wolfgang Gebauer / Stefan Tenzer / Jürgen Markl / 要旨: Nicotinic acetylcholine receptors (nAChR) play important neurophysiological roles and are of considerable medical relevance. They have been studied extensively, greatly facilitated by the gastropod ...Nicotinic acetylcholine receptors (nAChR) play important neurophysiological roles and are of considerable medical relevance. They have been studied extensively, greatly facilitated by the gastropod acetylcholine-binding proteins (AChBP) which represent soluble structural and functional homologues of the ligand-binding domain of nAChR. All these proteins are ring-like pentamers. Here we report that AChBP exists in the hemolymph of the planorbid snail Biomphalaria glabrata (vector of the schistosomiasis parasite) as a regular pentagonal dodecahedron, 22 nm in diameter (12 pentamers, 60 active sites). We sequenced and recombinantly expressed two ∼25 kDa polypeptides (BgAChBP1 and BgAChBP2) with a specific active site, N-glycan site and disulfide bridge variation. We also provide the exon/intron structures. Recombinant BgAChBP1 formed pentamers and dodecahedra, recombinant BgAChBP2 formed pentamers and probably disulfide-bridged di-pentamers, but not dodecahedra. Three-dimensional electron cryo-microscopy (3D-EM) yielded a 3D reconstruction of the dodecahedron with a resolution of 6 Å. Homology models of the pentamers docked to the 6 Å structure revealed opportunities for chemical bonding at the inter-pentamer interfaces. Definition of the ligand-binding pocket and the gating C-loop in the 6 Å structure suggests that 3D-EM might lead to the identification of functional states in the BgAChBP dodecahedron.
ダウンロード / ファイル: emd_2055.map.gz / 形式: CCP4 / 大きさ: 87.1 MB / タイプ: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES)
注釈
A negative temperature factor of 278.9 A^2 was applied to the map.
ボクセルのサイズ
X=Y=Z: 1 Å
密度
表面レベル
登録者による: 1.0 / ムービー #1: 1
最小 - 最大
-0.59094787 - 3.62690711
平均 (標準偏差)
0.14051077 (±0.43470621)
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
286
286
286
Spacing
286
286
286
セル
A=B=C: 286.0 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
1
1
M x/y/z
286
286
286
origin x/y/z
0.000
0.000
0.000
length x/y/z
286.000
286.000
286.000
α/β/γ
90.000
90.000
90.000
start NX/NY/NZ
-184
-184
-183
NX/NY/NZ
368
368
368
MAP C/R/S
1
2
3
start NC/NR/NS
0
0
0
NC/NR/NS
286
286
286
D min/max/mean
-0.591
3.627
0.141
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添付データ
-
試料の構成要素
-
全体 : Acetylcholine Binding Protein (AChBP) from Biomphalaria glabrata
全体
名称: Acetylcholine Binding Protein (AChBP) from Biomphalaria glabrata
要素
試料: Acetylcholine Binding Protein (AChBP) from Biomphalaria glabrata
タンパク質・ペプチド: Biomphalaria glabrata Acetylcholine Binding Protein
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超分子 #1000: Acetylcholine Binding Protein (AChBP) from Biomphalaria glabrata
超分子
名称: Acetylcholine Binding Protein (AChBP) from Biomphalaria glabrata タイプ: sample / ID: 1000 / Number unique components: 1
分子量
実験値: 1.86 MDa / 理論値: 1.86 MDa / 手法: SDS-PAGE
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分子 #1: Biomphalaria glabrata Acetylcholine Binding Protein
分子
名称: Biomphalaria glabrata Acetylcholine Binding Protein / タイプ: protein_or_peptide / ID: 1 / Name.synonym: BgAChBP 詳細: As yet, it is not entirely clear whether the dodecahedron is a homomeric assembly of either type one and/or two, or a heteromeric assembly of types one and two. コピー数: 60 / 集合状態: Dodecapentamer / 組換発現: No