ジャーナル: Nature / 年: 2015 タイトル: Subnanometre-resolution electron cryomicroscopy structure of a heterodimeric ABC exporter. 著者: JungMin Kim / Shenping Wu / Thomas M Tomasiak / Claudia Mergel / Michael B Winter / Sebastian B Stiller / Yaneth Robles-Colmanares / Robert M Stroud / Robert Tampé / Charles S Craik / Yifan Cheng / 要旨: ATP-binding cassette (ABC) transporters translocate substrates across cell membranes, using energy harnessed from ATP binding and hydrolysis at their nucleotide-binding domains. ABC exporters are ...ATP-binding cassette (ABC) transporters translocate substrates across cell membranes, using energy harnessed from ATP binding and hydrolysis at their nucleotide-binding domains. ABC exporters are present both in prokaryotes and eukaryotes, with examples implicated in multidrug resistance of pathogens and cancer cells, as well as in many human diseases. TmrAB is a heterodimeric ABC exporter from the thermophilic Gram-negative eubacterium Thermus thermophilus; it is homologous to various multidrug transporters and contains one degenerate site with a non-catalytic residue next to the Walker B motif. Here we report a subnanometre-resolution structure of detergent-solubilized TmrAB in a nucleotide-free, inward-facing conformation by single-particle electron cryomicroscopy. The reconstructions clearly resolve characteristic features of ABC transporters, including helices in the transmembrane domain and nucleotide-binding domains. A cavity in the transmembrane domain is accessible laterally from the cytoplasmic side of the membrane as well as from the cytoplasm, indicating that the transporter lies in an inward-facing open conformation. The two nucleotide-binding domains remain in contact via their carboxy-terminal helices. Furthermore, comparison between our structure and the crystal structures of other ABC transporters suggests a possible trajectory of conformational changes that involves a sliding and rotating motion between the two nucleotide-binding domains during the transition from the inward-facing to outward-facing conformations.
ダウンロード / ファイル: emd_6085.map.gz / 形式: CCP4 / 大きさ: 7.8 MB / タイプ: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES)
注釈
3D reconstruction of TmrAB in complex with Fab AH5
ボクセルのサイズ
X=Y=Z: 1.96 Å
密度
表面レベル
登録者による: 4.0 / ムービー #1: 4
最小 - 最大
-15.689664840000001 - 27.532846450000001
平均 (標準偏差)
0.0 (±0.99999994)
対称性
空間群: 1
詳細
EMDB XML:
マップ形状
Axis order
X
Y
Z
Origin
-64
-64
-64
サイズ
128
128
128
Spacing
128
128
128
セル
A=B=C: 250.88 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
1.96
1.96
1.96
M x/y/z
128
128
128
origin x/y/z
0.000
0.000
0.000
length x/y/z
250.880
250.880
250.880
α/β/γ
90.000
90.000
90.000
start NX/NY/NZ
0
0
0
NX/NY/NZ
96
96
80
MAP C/R/S
1
2
3
start NC/NR/NS
-64
-64
-64
NC/NR/NS
128
128
128
D min/max/mean
-15.690
27.533
0.000
-
添付データ
-
試料の構成要素
-
全体 : TmrAB in complex with Fab AH5
全体
名称: TmrAB in complex with Fab AH5
要素
試料: TmrAB in complex with Fab AH5
タンパク質・ペプチド: ABC exporter
タンパク質・ペプチド: Fab AH5
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超分子 #1000: TmrAB in complex with Fab AH5
超分子
名称: TmrAB in complex with Fab AH5 / タイプ: sample / ID: 1000 / 詳細: single particle; sample was monodisperse / 集合状態: One heterodimer with one Fab bound / Number unique components: 2