アミノ酸アンチポーターによる基板認識と輸送のメカニズム
Xiang Gao1, Lijun Zhou, Xuyao Jiao
1Ministry of Education Protein Science Laboratory, Tsinghua University, Beijing 100084, China.
Nature
|January 22, 2010
まとめ
E. coli のアミノ酸アンチポーター AdiC は,アルギニンとアグマチンを細胞膜に輸送する. その結晶構造は,アルギニンの結合が如何に形状の変化を引き起こし,輸送メカニズムを解明するかを明らかにします.
科学分野:
- 構造生物学 構造生物学とは
- バイオケミストリー バイオケミストリー
- 微生物学 微生物学とは
背景:
- E. coliのような腸内細菌は,酸性環境でAdiCアンチポーターを利用する.
- AdiCは細胞内アグマチンを細胞外アルギニンと交換し,陽子を放出する.
- AdiCは,アミノ酸-ポリアミン-オルガノケーション (APC) トランスポータースーパーファミリーに属しています.
研究 の 目的:
- アルギニンに結合したE. coli AdiCの結晶構造を決定する.
- AdiCによる基板認識と輸送のメカニズムを解明する.
主な方法:
- アルギニンに結合したE. coli AdiC変異体のX線結晶学で3.0 Å解像度.
主要な成果:
- 結晶構造は,酸性結合室に囲まれたアルギニンを明らかにします.
- アルギニン結合は,トランスメブランヘリックスTM6,TM2,TM10における構造的再編成を誘導し,オクラージュド・コンフォーメーションを引き起こします.
- アロマティック残留物とGlu 208を含む3つの潜在的なゲートを特定し,基板輸送を規制しました.
結論:
- この構造は,AdiCがアルギニンを認識し,結合する方法についての洞察を提供します.
- 基板結合時の形状の変化は,輸送機構にとって極めて重要です.
- 潜在的なゲーティングメカニズムは,アルギニンとアグマチンの輸送の異なる規制を示唆しています.
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