ニューロントランスミッター/ナトリウムシンポーター・オートログ LeuT には,単一の高親和性基板部位があります
Chayne L Piscitelli1, Harini Krishnamurthy, Eric Gouaux
1Department of Biochemistry and Molecular Biology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, USA.
Nature
|December 24, 2010
まとめ
神経伝達物質/ナトリウムシンポーター (NSSs) はシナプス機能に不可欠です. この研究では,LeuTには1つの高親近性結合部位しか存在しないことが明確に示され,2つのアロステリック結合部位を持つモデルが否定されました.
科学分野:
- 神経科学は神経科学である.
- 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
背景:
- 神経伝達物質/ナトリウムシンポーター (NSS) は,化学シナプスにおける神経伝達物質の再吸収を担当する重要な膜タンパク質です.
- NSSは神経学的疾患に関与しており,様々な薬剤の標的となっている.
- LeuTは,プロカリオットのNSSであり,NSSの構造-機能関係を理解するためのモデルとして機能します.
研究 の 目的:
- LeuTトランスポーター内の高親和性基板結合部位の数に関する論争を解決するために.
- LeuT.における2つの推定結合部位 (S1とS2) の間の提案されたアロステル結合を調査する.
主な方法:
- 準基質結合の直接測定は,同熱定位カロメトリー,均衡透析,スシンチレーション近接測定を用いて行われます.
- サブストラットの流動動性を分析するための吸収実験.
- 比較分析のために,野生型のLeuTとS2サイト変異体を使用した.
主要な成果:
- 実験データは, LeuT. の単一の,中央に位置する,高親和性基板結合部位 (S1) の存在を確認しています.
- 2番目の高親和結合部位 (S2) またはS1とS2間のアロステル結合の存在を裏付ける証拠は見つかりませんでした.
- 輸送動態は,単純な単一基板メカニズムによって正確に記述されます.
結論:
- LeuTは1つの高親和性基板結合部位しか持っていない.
- LeuTにおける2つのアロステリックカップリングされた結合部位を提案するモデルは,実験的証拠によって支持されていません.
- この発見は,NSS輸送のメカニズムを明確にし,関連する人間輸送機を理解するための意味を持つ.
関連する概念動画
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One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme “pump” embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...
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