マルトーストランスポーターの触媒介質の結晶構造
Michael L Oldham1, Dheeraj Khare, Florante A Quiocho
1Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
Nature
|November 23, 2007
まとめ
Escherichia coliのマルトーストランスポーターは,糖を移動するためにATP結合カセット (ABC) トランスポーターを使用します. その結晶構造は,マルトースが結合タンパク質からトランスポーターにどのように移動するかを明らかにし,効率的な吸収を確保します.
科学分野:
- バイオケミストリー バイオケミストリー
- 構造生物学 構造生物学とは
- 分子生物学は分子生物学である.
背景:
- Escherichia coliのマルトース吸収システムは,ATP結合カセット (ABC) トランスポータースーパーファミリーの重要な例です.
- ABCトランスポーターのメカニズムの理解は,様々な生物学的プロセスと薬の開発に不可欠です.
研究 の 目的:
- 完ぺきなマルトーストランスポーター複合体の高解像度結晶構造を決定するために.
- ATP結合カセットダイマーとマルトース結合タンパク質によって媒介されるマルトース転位のメカニズムを解明するため.
主な方法:
- X線結晶学を用いて,マルトーストランスポーターの2.8-Åの結晶構造を得ました.
- ATPの水解を阻害する特定の変異が,ATPに結合した形状でトランスポーターを安定させるために使用されました.
主要な成果:
- 結晶構造は,マルトース結合タンパク質,マルトース,ATPと複合した無傷のマルトーストランスポーターを明らかにします.
- マルトースは,トランスメブランサブユニットの間の空洞に隔離され,結合タンパク質が入り口を封じ込めます.
- ATPを結合するカセットダイマーは,ATPを結合した閉じた形状を採用しています.
結論:
- この構造は,協調された輸送機構の直接的な証拠を提供します.
- 溶液の移転は,ATP結合カセットダイマーの閉塞に伴い,ATPの水解と組み合わせて起こります.
- マルトース結合タンパク質はゲートキーパーとして作用し,一方向の砂糖転移を保証します.
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