膜キャリアの転位経路における残留物の識別
1Department of Physiology, Johns Hopkins University Medical School, Baltimore, Maryland 21209.
Cell
|October 8, 1993
まとめ
システイン残留物は,E. coliのグルコース6フォスファートトランスポーター (UhpT) 機能に不可欠ではありません. しかし,C265は,基板経路に直接接しているため,輸送に不可欠です.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- メンブレーン輸送 メンブレーン輸送
背景:
- UhpTは,E. coliのアニオン交換タンパク質で,グルコース6リン酸輸送を促進します.
- 以前の研究では,システイン残留物がUhpTの動作に不可欠ではないことが示されました.
研究 の 目的:
- 特定のシステイン残留物 (C143およびC265) のUhpT機能および基板輸送における役割を調査する.
- E. coli の膜内のC143とC265の位置とアクセシビリティを決定する.
主な方法:
- 誘導性変異は,システインの必要性を評価するために使用されました.
- システインのアクセシビリティを検証するために,p-クロロマーキュリベンゾスルフォネート (PCMBS) との反応が採用されました.
- PCMBSのアクセシビリティに対するグルコース6フォスファートの効果を評価するために,基板結合アッセイが行われました.
主要な成果:
- システイン残留物は,UhpTの基本的な輸送機能には必要ありません.
- C143は細胞膜の細胞質側に位置しています.
- C265は,膜の両側からアクセスでき,PCMBSによるその改変は,グルコース6酸化物によってブロックされます.
結論:
- C265は機能に不可欠ではないが,UhpTの輸送機構において重要な役割を果たしている.
- C265は,グルコース6フォスファートトランスポーターの基板転位経路内に位置しています.
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